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POPULAR 



CHEMISTRY 



BY 



J. DORMAN STEELE, Ph.D. 



AUTHOR OF A SERIES IN THE NATURAL SCIENCES 







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AMERICAN BOOK COMPANY 

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Popular Chemistry, . . 

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Fourteen Weeks in Botany, . 
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Copyright, 1887, by A. S. Barnes & Co. 
Copyright, 1897, by American Book Company. 



Pop. Chem. 
w. P. 3 



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v 



PUBLISHERS' PREFACE. 



QUINCE the publication of the revised edition 
^-^ of Steele's " Fourteen Weeks in Chemistry," 
in 1873, the study has grown greatly in popu- 
larity in the schools of this country. Under such 
circumstances, it has seemed advisable to enlarge 
somewhat upon the former treatment of the sub- 
ject; and to meet this change of feeling on the 
part of teachers, the present work has been pro- 
vided. 

The simplicity of statement and clearness of 
method which are the characteristics of Professor 
Steele's previous text-books in Chemistry, and of all 
his other works, have been fully demonstrated by 
an ever-increasing popular demand. No change in 
method of treatment has been made in the present 
work, beyond that necessitated by new discoveries 
in this branch of science. 



iv PUBLISHERS' PREFACE. 

In its new form, there will be found many 
graphic illustrations, made expressly for this edition. 
The typographical appearance of the book has also 
been greatly improved. We trust that we have pre- 
pared a text-book that will meet the wants of both 
teachers and pupils. 



PREFACE 



TO THE FIRST EDITION 



IN the preparation of this little volume the author 
lays no claim to originality : his has been the far 
humbler task of endeavoring to express, in simple, 
interesting language, a few of the principles and 
practical applications of Chemistry. There is a large 
class of pupils in our schools who can pursue this 
branch only a single term, the time assigned to it in 
most institutions. They do not intend to become 
chemists, nor even professional students. If they wan- 
der through a large text-book, they become confused 
by the multiplicity of strange terms, which they can 
not tarry to master, and, as the result, too often only 
"see men as trees walking." Attempts have been 
made to reach this class by omitting or disguising 
the nomenclature ; but this robs the science of its 
mathematical beauty and discipline, while it does not 
fit the student to read other chemical works or to 
understand their formulae. The author has tried to 
meet this want by omitting that which is perfectly 
obvious to the eye — that which everybody knows 
already — that which could not be long retained in 
the memory — and that which is essential only to the 



VI PKEFACE TO THE FIRST EDITION. 

chemist. He has not attempted to write a reference- 
book, lest the untrained mind of the learner should 
become clogged and wearied with a multitude of de- 
tail He has sought to make a pleasant study which 
the pupil can master in a single term, so that all its 
truths may become to him " household words." Bot- 
any, Natural Philosophy, and Physiology are omitted, 
since they are now pursued as separate branches. 
Unusual importance is given to that practical part 
of chemical knowledge which concerns our every-day 
life, in the hope of bringing the school-room, the 
kitchen, the farm, and the shop in closer relationship. 
This work is designed for the instruction of youth, 
and for their sake clearness and simplicity have been 
preferred to recondite accuracy. If to some young 
man or woman it becomes the opening door to the 
grander temple of Nature beyond, the author will be 
abundantly repaid for all his toil. 



PREFACE 

TO THE REVISED EDITION 



SIX years ago, at the solicitation of his fellow- 
teachers, the author offered this work to the 
profession. Having been prepared for the use of his 
own classes, and embodying his oral instructions, it 
naturally partook of the peculiarities of that method. 
The desire was to interest pupils in scientific study. 
He believed that a chemical fact is no less a truth 
because made attractive by an imaginative garb. If 
thus a child could be won to its consideration, the 
intrinsic beauty of the subject would lure him on, 
and so at last he would come to pursue it into the 
labyrinths of dry, technical works. 

The hearty reception of the book at once and its 
constantly increasing sale, the demand for an entire 
series on the same plan, words of approval from 
educators whose commendation it was a great satis- 
faction to have won, the fact that several other 
series based upon the same general idea have since 
appeared, and, above all, the assurance that the books 
have gone into hundreds of schools where science 
had never been taught before — have convinced the 
author of the inherent correctness of his view. 



Vlll PREFACE TO THE REVISED EDITION. 

A demand having arisen for the admission of the 
new nomenclature into the book, the opportunity is 
gladly taken of making such revision as the daily 
use of the work in the class-room, and the advice of 
others, have suggested. 

The author would here acknowledge his special 
indebtedness to the many teachers who, sympathizing 
with his plan of popularizing science, have pointed 
out what they considered defects in its execution, 
and given him the benefit of such illustrations and 
methods as they have found serviceable. The value 
of these criticisms has been shown in the increased 
worth of each edition of this series. 

The usual authorities have been freely consulted 
in this revision. The following have been found of 
especial service : Miller's Elements of Chemistry (4th 
London Edition), Tomlinson's Miller's Inorganic Chem- 
istry, Roscoe's Lessons in Chemistry (London, 1869), 
Bloxam's Metals, and Fownes' Manual of Chemistry 
(London, 1873). In addition, reference has been had 
to the works of Cooke, Draper, Nichols, Fresenius, 
Muspratt, Faraday, Watts, Stockhart, Mofflt, Gmelin, 
Griffin, Tyndall, Odling, Noad, Williamson, Wilson, 
Galloway, Youmans, Regnault, Thomson, Valetin, 
Gregory, Porter, Will, and many others. 



SUGGESTIONS TO TEACHERS. 



IT is advised that in the use of this book the top- 
ical method of recitation should be adopted. So 
far as possible, the order of the subjects is uniform 

—Viz., OCCURRENCE, PREPARATION, PROPERTIES, USES, 

and Compounds. The subject of each paragraph indi- 
cates a question which should draw from the pupil 
the substance of what follows. At each recitation 
the scholar should be prepared to explain any point 
passed over during the term, on the mention of its 
title by the teacher. Such reviews are of incalcu- 
lable value. While some are reciting, let others write 
upon specified topics at the blackboard, after which 
the class may criticise the thought, the language, 
the spelling, and the punctuation. Never allow a 
pupil to recite a lesson, or answer a question, except 
it be a mere definition, in the language of the book. 
The text is designed to interest and instruct the 
pupil ; the recitation should afford him an oppor- 
tunity of expressing what he has learned, in his 
own style and words. Every pupil should keep a 
note-book, in which to record under each general 
head of the text-book all the experiments, descrip- 
tions, and general information given by the teacher 
in class. In order to accustom the scholar to the 



X SUGGESTIONS TO TEACHERS. 

nomenclature, use the symbols constantly from the 
beginning ; they may seem dull at first, but if every 
compound be thus named, a familiarity with chem- 
ical language will be induced that will be as pleas- 
ing as it will be profitable. If time will admit, in 
addition, have weekly essays prepared by the class, 
combining information from every attainable source. 

Ocular demonstration is absolutely necessary to 
any progress in the study of chemistry. Simple 
directions with regard to the experiments are given 
in the Appendix (see page 2 61) which will enable 
the unprofessional chemist to perform them readily, 
and, in case it is convenient for the pupils to work 
in the laboratory, will guide them in their investi- 
gations. The subject of Qualitative Analysis is also 
explained so clearly, and the directions are so com- 
plete (see page 288), that even the amateur student 
can grasp the subject and demonstrate its principles. 

Teachers desiring pleasant information to relieve 
the recitation hour, will find it in that delightful 
work of Dr. Nichols, Fireside Science. Many curious 
and entertaining stories and facts are given in a 
book entitled Treasures of the Earth. For common 
works of reference, Roscoe & Schorlemmer's Treatise 
on Chemistry, 6 vols, octavo, or Miller's Elements of 
Chemistry, 3 vols, octavo, will be most generally 
useful. 



TABLE OF CONTENTS. 



I.— I NTRODUCTION. 

PAGE 

DEFINITIONS ! 1 

CONSTITUTION OF BODIES 3 

NOTATION AND NOMENCLATURE 5 

CLASSIFICATION OF ELEMENTS 6 

ORGANIC AND INORGANIC CHEMISTRY 7 

II.— INORGANIC CHEMISTRY. 

1.— THE NON-METALS. 

Oxygen, Ozone 11 

Weighing and Measuring Gases 24 

Nitrogen, Nitric Acid, Nitrous Oxide, etc 27 

Hydrogen, Water, etc 38 

Carbon, Carbon Dioxide, Coal-Gas, etc 53 

Combustion 75 

The Atmosphere 85 

The Halogens, Chlorine, Hydrochloric Acid, Acids, 

Bases, Salts, Bromine, Iodine, Fluorine 92 

Sulphur, Sulphuric Acid, etc 103 

Valence Ill 

Phosphorus, Matches, etc 113 

Arsenic 117 

Boron 120 

Silicon, Glass, etc „ . 122 



Xll TABLE OF CONTENTS. 

2,— THE METALS. PAGE 

Potassium „ 127 

Sodium 131 

Ammonium 136 

Calcium 138 

Strontium and Barium 143 

Magnesium 144 

Aluminium, Clay 145 

Spectrum Analysis 147 

Iron, Steel, Bessemer 's process, etc 150 

Zinc 158 

Tin 160 

Copper 161 

Lead 162 

Gold 165 

Silver, Photography, etc 167 

Platinum 173 

Mercury, Mirrors, etc 174 

The Alloys 176 

Review of the Properties of the Metals 179 

III.— ORGANIC CHEMISTRY. 

INTRODUCTION 185 

The Paraffines and their Derivatives 189 

The Alcohols... 193 

Fermentation, Beer, Wine, etc 195 

Aldehydes and Acids, Vinegar, Acetic Acid, Oxalic 

Acid, etc . . . 200 

Ethers and Ethereal Salts, Fats, Glycerin, Soap, 

etc 204 



TABLE OF CONTENTS. Xlll 

PAGE 

Halogen Derivatives, Chloroform, Chloral, etc 209 

The Carbohydrates, Starch, Cellulose, Sugar 211 

Aromatic Compounds, Benzene, Aniline, etc 221 

Terpenes and Camphors, Essential Oils, Resins, Bal- 
sams, Rubber 225 

Alkaloids, Morphine, Quinine, Nicotine, Strychnine, 

etc 231 

Dyes and Dyeing, Tanning, etc 235 

Albuminous Bodies 239 

Domestic Chemistry 243 

CONCLUSION, Chemistry of the Sunbeam, etc 249 

I V.— APPENDIX, 

Table of the Elements 257 

Names and Formulas of the more Important Chemicals . . . 258 

Directions for Experiments 261 

Qualitative Analysis 288 

Questions for Class Use 304 

Index 321 

Glossary 325 

List of Chemicals and Apparatus 328 



Introduction 



" I sympathize with that beautiful idea of Oersted, which he expressed 
in the now familiar phrase, l TJie laws of Nature are tJie thoughts of God: 
* * * Through the great revolutions which have taken place in the 
forms of thought, the elements of truth in the successive systems have 
been preserved, while the error has been as constantly eliminated ; and so, 
as I believe, it always will be, until the last generalization of all brings us 
into the presence of that law which is indeed the thought of G-od." 

J. P. Cooke, Jr. 



AVOGADRO'S LAW. 

" Equal volumes of all substances, when in a state 
of gas, and under like conditions, contain the same 
number of molecules." See Physics, p. 23. 



THE 



ELEMENTS OF CHEMISTRY. 



I NTRODUCTI ON. 

Chemistry treats of the composition of substances, 
and all changes in composition which may take place. 

All the changes, or phenomena, which matter 
exhibits, may be divided into two groups: 1st. Those 
in which the composition is not altered. 2d. Those 
in which a change in composition takes place. The 
first are physical phenomena, the second are chemical 
phenomena. 

Examples: 1st. Fall of a stone, vibration of a 
tuning-fork, and all phenomena of motion ; boiling of 
water, magnetizing of iron. 2d. Rusting of iron, 
souring of milk, burning of candle. 

No destruction of matter is possible. When a 
substance disappears, as in the boiling of water or 
the burning of a candle, this is because it is changed 
into an invisible form (gas), and not because it has 
been destroyed. In its new form it still has the 
properties of weight and impenetrability, which prove 
it to be matter. 

An Element is a kind of matter which has never 
been separated into other substances. — Examples : 



2 ELEMENTS OF CHEMISTRY. 

gold, sulphur. The number of elements now known 
is about seventy.* The larger number of these are 
rare. A few of the elements occur naturally, but 
-most substances are composed of two or more ele- 
ments, and are therefore called compounds. 

Compounds, in their properties, are in general 
very unlike their elements. \ — Examples : yellow sul- 
phur and white quicksilver form red vermilion ; inert 
charcoal, hydrogen, and nitrogen produce the deadly 
prussic acid ; solid charcoal and sulphur make a 
colorless liquid ; poisonous and offensive chlorine 
combines with the brilliant metal sodium to form 
common salt. 

Chemical Affinity, or Chemism, is the name given 
to that power which causes the chemical union of 
substances, and which holds the elements together 
in compounds. It acts only at insensible distances, 
and generally with great energy. J If chemism should 
suddenly cease, not only would all chemical action 
be impossible, but almost all substances would at 
once change their character ; for all compounds 
would be resolved into their elements: — all water 
would disappear into two invisible gases, the solid 
rocks would fall to powder, and all animal and 



* It is not probable that the list is complete, but we can not suppose 
that any very abundant element is yet to be found. 

t " The elements have no more likeness to the compounds which they 
form than the separate letters of the alphabet have to the words which 
may be made from them."— Miller. 

X Nothing in the nature or appearance of an element indicates its 
chemical affinity, and it is only by trial that we can tell with what it will 
combine. This attraction is not a mere freak of nature, but is imparted to 
matter by God Himself. 



INTRODUCTION. 8 

vegetable substances would be changed into three 
gases and a substance like charcoal. 

Heat and Light favor chemical action, and fre- 
quently develop an affinity where it seems to be 
wanting. The former, especially, tends to drive the 
elements of a compound without the range of old 
attractions and within that of new ones. Electricity 
is also a powerful agent in producing chemical ac- 
tion. — Examples : gun-cotton, when lying in the air, 
is apparently harmless, but a spark of fire will pro- 
duce a brilliant flash, and cause it to disappear as a 
gas ; nitrate of silver in contact with organic matter 
turns black, by the action of the light ; an electric 
current led through acidulated water decomposes it 
into its constituent gases. 

Solution aids in chemical change, as it permits 
the particles of substances to come within the range 
at which chemism can act. — Example : sodium car- 
bonate* and tartaric acid mixed in a glass will not 
combine, but the addition of water will cause a 
violent effervescence. 

Law of Definite Proportions. — Chemical combina- 
tion always takes place between definite weights of 
substances. 

Law of Multiple Proportions. — If two elements, 
A and B, combine in different proportions, the relative 
quantities of B which combine with any fixed quan- 
tity of A bear a simple ratio to one another. 

Constitution of Bodies. — The phenomena of both 
Physics and Chemistry lead to the conclusion that 

* Carbonate of Soda. 



4 ELEMENTS OF CHEMISTKY. 

all bodies are made up of minute particles which 
are never in actual contact with each other, and are 
always in motion. In any given substance, all the 
constituent particles are alike and of the same com- 
position as the substance. These particles are called 
molecules. A molecule is the smallest particle of a 
substance ivhich can exist in the free state. A phys- 
ical change goes no further than the molecule, and 
hence does not affect the nature of the substance ; 
but a chemical change is a change of substance, and 
hence must consist in the breaking up of molecules 
and the formation of new ones. This is explained 
by the assumption that the molecules are compound, 
each molecule being composed of still smaller parti- 
cles. These smaller particles are called atoms, and 
may be defined as the indivisible constituents of mole- 
cules. They are the smallest particles of elements 
which can take part in chemical changes. Thus a 
molecule consists of atoms held together by chemism. 
In an element, the molecules are made up of atoms 
of the same kind ; in a compound, the molecules 
consist of atoms of different kinds. 

Atoms differ from each other in chemism, in 
weight, and in valence. 

The Atomic Weight of an element expresses the 
weight of its atom compared with that of the atom 
of hydrogen. 

Molecular Weight is the sum of the weights of 
the atoms in the molecule. 

Valence* is the property of an atom by virtue of 

* The property of valence is treated on page 111. 



INTRODUCTION. 

which it can hold a definite number of other atoms 
in combination. 

Chemical Notation. — For the sake of brevity, 
chemists use a kind of short-hand. An atom is 
represented by the first letter of its English name. 
When that would produce confusion, the Latin initial 
is substituted, and in some cases a second letter 
added. — Examples : carbon and chlorine both com- 
mence with C ; so the latter takes CI for its symbol. 
Silver and silicon both begin with Si, hence the 
former assumes Ag, from its Latin name, Argentum. 
If more than one atom of an element is contained 
in a molecule of a compound, this is shown by 
writing the number below the symbol. — Example : 
H 2 indicates that in a molecule of water there are 
two atoms of hydrogen and one of oxygen. 

Molecules are represented by grouping together 
the symbols of their constituent atoms. Such a 
group of symbols is called the formula of the mole- 
cule or substance. 

Chemical action or "reaction" between substances 
is expressed by means of chemical equations which 
resemble those of algebra, and whose terms are mo- 
lecular formulas. — Example : NaCl + AgN0 3 = NaN0 3 + 
AgCl. The sign + indicates mixture ; the sign =, 
conversion into. 

Nomenclature. — The elements which were known 
anciently retain their former names. Those discov- 
ered more recently are named from some peculiar- 
ity. — Examples : chlorine, from its green color ; bro- 
mine, from its bad odor. The uniform termination 



b ELEMENTS OF CHEMISTRY. 

ium has been given to the lately found metals. — 
Examples: potassium, sodium. A similarity of end- 
ing in non-metallic elements indicates some analogy. 
— Examples : silicon, boron ; iodine, bromine. 

Compounds are named from their constituent 
atoms. When a compound contains only two ele- 
ments (a binary compound), the names of the two 
are placed together and one (the non-metal) takes the 
termination ide. Thus, potassium and iodine form 
the compound which is written KI, and read potas- 
sium iodide ; sodium and chlorine, NaCl, sodium 
chloride ; zinc and oxygen, ZnO, zinc oxide. 

Other rules for nomenclature will be noticed as 
occasion demands. 

Classification of the Elements. — The elements are 
usually divided into two classes : Metals and Non- 
metals. The metals, as a class, are electro-positive * 
with reference to the non-metals, or what amounts 
to the same thing, the non-metals are electro-nega- 
tive* in their behavior toward the metals. The 
metals are the basef-forming elements, the non- 
metals the acid f-f orming elements. These classes, 
however, are not separated by any sharply defined 
difference in properties, but one shades gradually 
into the other : — all the elements may be arranged 
in a series in such a way that each is electro-posi- 
tive toward all which follow it, and electro-negative 
toward all which precede it; and certain elements 

* See definition of these terms under Electricity in Steele's "Popular 
Physics." 

t See explanation of these terms on pages 98 and 99. 



INTRODUCTION. 7 

are found to form both acids and bases. Thus the 
division is a somewhat arbitrary one, and is retained 
chiefly for convenience of study. 

Organic and Inorganic Chemistry. — The division 
of Chemistry into organic and inorganic Chemistry 
is still kept, though the significance of the names 
has changed. It was formerly thought that " organic" 
substances could be produced only by the agency 
of plant or animal life, and thus formed a group 
quite distinct from the u inorganic" or mineral sub- 
stances. But it has been found that many " organic " 
substances can be made in the laboratory from 
" inorganic " substances without the aid of the vital 
process. The organic substances always contain car- 
bon, and include most of the compounds into which 
this element enters, so that organic Chemistry is 
now defined as the Chemistry of the Compounds of 
Carbon, while inorganic Chemistry deals with the 
compounds of the other elements. 



II. 

Inorganic Chemistry. 



" In the de-oxidation and re-oxidation of the hydrogen in a single drop 
of water, we have before us, so far as force is concerned, an epitome of 
the whole of life."— Hinton. 



INORGANIC CHEMISTRY. 



THE NON-METALS. 
OXYGEN. 

Symbol, Atomic Weight, 16 Specific Gravity, 1.1. 

The name Oxygen means acid-former, and was 
given because it was supposed to be the essential 
principle of all acids. 

Occurrence. — is the most abundant of all the 
elements — comprising by weight f of the water, f of 
all animal bodies, about % of the crust of the earth, 
and more than -J- of the air. 

Preparation. — Although is present in the air in 
large quantities, it can not be readily obtained from 
this source, but is usually prepared from one of its 
compounds by heat. Thus, if oxide of mercury is 
heated, it yields and mercury. We may represent 
the chemical change which takes place by a chem- 
ical equation : 

HgO = Hg + ; 

which is read, oxide of mercury is converted into, 
or gives, mercury and oxygen. The equation ex- 
presses more than the mere fact that this change 
has taken place ; for each atomic symbol stands for 



12 INORGANIC CHEMISTRY. 

a definite weight of the element which it represents, 
and the equation consequently means, 216 parts of 
oxide of mercury give 200 parts of mercury and 
16 parts of oxygen. 

Another substance which yields readily when 
heated is potassium chlorate (KC10 3 ). The best 
method of preparing for experimental purposes is 
to heat a mixture of equal parts of this substance 
and manganese dioxide (Mn0 2 ).* The manganese 
dioxide remains unchanged, but in some way which 
is not understood, causes the potassium chlorate to 
give off its at a lower temperature and more 
regularly than when it is heated alone. The mixed 
substances are heated in a flask and the gas collected 
over water in a pneumatic trough, as shown in the 
illustration. 

The reaction may be represented thus : 

KC10 3 = KC1 + 30 
39 + 35.5 + 48 39 + 35.5 3x16 



122.5 74.5 48 



122.5 



The obtained will be yl^ of the potassium 
chlorate used, i.e., every 122.5 parts by weight 
(grs., oz., or lbs.) will yield 48 parts (grs., oz., or lbs.) 
of 0, and 74.5 parts (grs., oz., or lbs.) of KC1. 

Properties. — has no odor, color, or taste. It is 
but very slightly soluble in water. It combines with 



; 



* This substance is sometimes known as binoxide of manganese, and, 
because of its color, as the black oxide of manganese. 







13 



Collecting O over water. 



every element except fluorine, helium, and argon. 
From some of its compounds it escapes explosively 
on the slightest blow, while from others it can be 
liberated only by the most powerful means. Its 
action on a substance is called oxidation of the sub- 
stance, and the products are oxides. It is incombusti- 
ble, but a vigorous supporter of combustion. 

The following experiments will illustrate its chem- 
ical energy. 

1. By blowing quickly upward upon a candle, ex- 
tinguish the flame, and leave a glowing wick. If 
this be plunged into a jar of 0, the coal will burst 
into a brilliant blaze. The experiment may be 
repeated many times before the will be exhausted. 



14 



INORGANIC CHEMISTRY. 



Fig. 2. 




Sulphur in O. 



Fig. 3. 



A new colorless gas, C0 2 , called carbon dioxide ("car- 
bonic acid") is formed by the combustion. 

2. Ignite a bit of sulphur 
placed in a " deflagrating spoon " 
(see Appendix, p. 264), and 
lower it into a jar of 0. It will 
burn with a beautiful blue light, 
and the formation of sulphur 
dioxide, S0 2 (" sulphurous acid"), 
which has the pungent odor of 
a burning sulphur match. 

3. Straighten one end of a 
watch-spring and fasten it in a bit of thin board ; 
heat the other end slightly and dip it into powdered 

sulphur. Light this and plunge 
it into a jar of 0, closing the 
mouth of the jar with the board. 
The burning sulphur will ig- 
nite the steel, which will burn 
without flame with a shower 
of fiery stars, while melted glob- 
ules of the oxide of iron (Fe 3 4 ) 
will fall upon the bottom of 
the jar. 

4. Place in the bottom of a deflagrating spoon a 
little fine, dry chalk ; then wipe a bit of phosphorus, 
about the size of a pea, very carefully and quickly 
between .pieces of blotting-paper ; lay this upon the 
chalk, and, holding the spoon over a large jar of 0, 
ignite the phosphorus with a heated wire, and lower 
it steadily into the gas. The phosphorus will burst 




A watch-spring in O. 



OXYGEN. 



15 




PhosjJhorus in O. " The phosphoric sun." 



into a flood of blinding light, while dense fumes of 
phosphorus pentoxide, 
P 2 5 , will roll down the 
.sides of the jar. 

5. Make a little tas- 
sel of zinc-foil, tip the 
ends with sulphur as 
in the 3d experiment, 
ignite and lower into a 
jar of 0. It will burn 
with a dazzling light, 
forming zinc oxide 
(ZnO). 

6. If a piece of char- 
coal-bark be ignited and 

lowered into a jar of 0, it will deflagrate with bright 
scintillations. 

Oxygen the Active Agent of the Air. — The burn- 
ing of substances in air resembles the burning in 0, 
except that it is never so energetic. It is, indeed, a 
true oxidation, and the oxides formed are the same 
as those produced in the we prepare. The burn- 
ing candle gives off C0 2 , sulphur S0 2 , phosphorus 
P 2 5 , the glowing iron which the blacksmith draws 
from his forge forms scales of Fe 3 4 , which fly 
blazing in every direction under the blows of his 
hammer.* Comprising about one fifth of the com- 
mon air, is ever-present, ever-waiting. 

* Quite in contrast to this pyrotechnic display is the action of the O 
upon the Fe contained in writing-fluid. At first the words are pale and 
indistinct, but in a few hours the O, noiselessly combining with the metal 
(see p. 17), brings out every letter in clear, bold characters upon the page. 



16 IKOBGAKIC CHEMISTRY. 

We open the damper of the stove and the air 
rushes in. The immediately attacks the heated 
fuel. Every two atoms combine with an atom of C 
and fly off into the air as C0 2 . 

The water of a river becomes foul from the dis- 
charge of drains and sewers. As it flows along, ex- 
posed to the air, the dissolves in it, attacks each 
particle of organic impurity and slowly burns it up ; 
thus rendering the river-water once more fit for use. 

We wipe our knives and forks, and lay them 
carefully away ; but if we have left on them a par- 
ticle of moisture, since H 2 favors chemical change, 
the will find it, and corrode the steel.* 

An animal dies, and the is an important agent in 
removing its body. The molecules which have been 
used to perform the functions of life, are broken up by 
the 0, and their atoms enter into new combinations. 

in the Human System. — We take the air into 
our lungs. Here the blood f absorbs the 0, and bears 
it to all parts of the body, depositing it wherever 
it is needed. Laden with this life-giving element, 
the vital fluid sweeps tingling through every artery 
to the remotest capillary tubes, sends the quick 
flush to the cheek, combines with a portion of the 



* The compound here formed will be a higher oxide than that produced 
at the blacksmith's forge, since a portion of the O was there prevented from 
uniting with the iron by the heat. It will be the red oxide of iron (Fe 3 3 , 
ferric oxide), or common iron rust, as we see it on stoves and other utensils. 

t " The blood is full of red corpuscles or cells containing Fe. These are 
so tiny, that a million of them cluster in the drop which will cling to the 
point of a needle. Quickly assuming a tawny hue, like the decayed leaves 
of autumn, they change so rapidly that 20,000,000 perish with every breath." 
—Draper. 



O X Y G E X . 17 

food thrown into the circulation from the stomach, 
breaks up every worn-out tissue, burns up the mus- 
cles as they do their work, until at last it comes 
back through the veins dark and thick with the 
products of the combustion — the cinders of the flame- 
less fire within us. 

Combustion and Heat. — All ordinary processes of 
decay and fire, are produced by the action of on sub- 
stances, and are different forms of oxidation. They 
differ only in the time employed in the operation. 
If unites rapidly, we call it fire ; if slowly, decay. 
Yet the process and the products are the same. A 
stick of wood is burned in the stove, and another 
rots in the forest, but the chemical change is iden- 
tical. In the oxidation of an atom of C, a certain 
amount of heat is produced. Hence, the house that 
decays in fifty years, gives out as much heat during 
that time as if it had been swept off by a fierce con- 
flagration in as many minutes. 

The Igniting Point of any substance is the tem- 
perature at which "it catches fire/' We elevate the 
heat of a small portion to the point of rapid union 
with 0, and that part in burning will give off heat 
enough to support the combustion of the rest. — 
Example : In making a fire, we take paper or shav- 
ings, which, being poor conductors of heat, and ex- 
posing a large surface to the action of 0, are easily 
raised to the required temperature. Having thus 
obtained sufficient heat to start the combustion of 
chips or pine sticks, we gradually increase it until 
there is enough to ignite the coal or wood. 



18 INORGANIC CHEMISTRY. 

Extinguishing Fires. — Blowing on a candle or 
lamp extinguishes it, because it lowers the heat of 
the flame below the igniting point of the gases. 
Fires are put out by water partly for the same reason, 
and also because it envelops the wood and shuts off 
the air. If a person's clothes take fire, the best 
course is to wrap him in a blanket, carpet, coat, or 
even in his own garments. This smothers the fire 
by shutting out the 0. Great care should be taken in 
a fire not to open the doors or windows, so as to cause 
a draught of air. The entire building may burst 
into a blaze, when the fire might have languished 
for want of 0, and so have been easily extinguished. 

Spontaneous Combustion. — Sometimes substances 
absorb oxygen from the air so rapidly, that heat 
enough is evolved to cause ignition ; or if the sub- 
stances are incombustible, other bodies in contact 
with them may be kindled. 

The waste cotton used in mills for wiping oil from 
the machinery, when thrown into large heaps, often 
absorbs from the air so rapidly that it bursts into 
a blaze. Fires are often started in this way, both in 
manufactories and on board ship. Similar cases of 
spontaneous combustion occur in hay-ricks in which 
the hay has been put up damp. 

Heaps of coal take fire from the oxidation of the 
iron pyrites contained in them. This is favored by 
the moisture of the air. 

All supposed instances of spontaneous combustion 
in the human body have been proved to be mistakes 
or deceptions. 



OXYGEN. 19 

The Human Furnace. — The body is like a stove 
in which fuel is burned, and the chemical action re- 
sembles that in any other stove. This combustion pro- 
duces heat, and our bodies are kept warm by the 
constant fire within us. We thus see why we fortify 
ourselves against a cold day by a full meal. When 
there is plenty of fuel in our human furnaces, the 
burns that ; but if there is a deficiency, the de- 
structive must still unite with something, and 
so it combines with the flesh ; — first the fat, and the 
man grows poor ; then the muscles, and he grows 
weak ; finally the brain, and he becomes crazed. 
He has burned up, as a candle burns out to dark- 
ness. 

Produces Motion. — As soon as we begin to per- 
form any unusual exercise, we commence breathing 
more rapidly, showing that, in order to do the work, 
we need more to unite with the food* and mus- 
cles. In very violent labor, as in running, we are 
compelled to open our mouths, and take deep inspi- 
rations of 0. This increased fire within elevates the 
temperature of the body, and we say "we are so 
warm that we pant." Really it is the reverse. The 
panting is the cause of our warmth. 

During sleep the organs of the body are mostly 
at "rest, except the heart. To produce this small 
muscular exertion very little is required. As our 
respiration is, therefore, slight, our pulse sinks, the 

* It is probable that a portion of our food, especially the carbonaceous, 
is oxidized directly without becoming an integral part of the body; but 
oxidation takes place in the tissues of all parts of the body, the oxygen 
being carried by the red-blood corpuscles. 



20 INORGANIC CHEMISTRY. 

heat of our body falls, and we need much additional 
clothing to keep warm.* Thus we require not 
only to keep us warm, but also to do all our work. 
Cut off its supply, and we grow cold ; the heart 
struggles spasmodically for an instant, but the mo- 
tive power is gone, and we soon die. 

How Gives us Strength. — Our muscles, as well 
as the food from which they are formed, consist of 
complex organic bodies, and the pent-up energy is 
very great. Thus in flesh, starch, sugar, etc., the 
molecules are very complex (see p. 188), and when 
these oxidize into the simpler ones of water, carbonic 
acid, and ammonia, the potential energy is trans- 
formed into heat and muscular strength, f As no mat- 
ter is either lost or gained in any chemical change, 
so also no energy is lost or gained, but all must 
be accounted for. 

The Burning of the Body by 0. — A man weighing 
150 lbs. has 64 lbs. of muscle. This will be burned 
in about 80 days of ordinary labor. As the heart 
works day and night, it burns out in about a month. 
So that we have a literal "new heart" every thirty 
days. We thus dissolve, melt away in time, and 
only the shadow of our bodies can be called our 

* Animals that hibernate show the same truth. The marmot, for 
instance, in summer is warm-blooded; in the winter its pulse sinks from 
140 to 4, and its heat corresponds. The bear goes to his cave in the fall, 
fat ; in the spring he comes out lean and lank. Cold-blooded animals have 
very inferior breathing apparatus. A frog, for example, has to swallow air , 
by mouthfuls, as we do water. Others have no lungs at all, and breathe 
in a little air through the skin, enough barely to exist. Is it strange they 
are cold-blooded? 

+ See discussion of energy and the transformation of potential into 
kinetic energy in "Steele's Popular Physics." 



OXYGEN. 21 

own. They are like the flame of a lamp, which 
appears for a long time the same, since it is " cease- 
lessly fed as it ceaselessly melts away." The rapidity 
of this change in our bodies is remarkable. Says 
Dr. Draper : " Let a man abstain from water and 
food for an hour, and the balance will prove he has 
become lighter." This action of 0, so destructive- 
wasting us away constantly from birth to death — 
is yet essential to our existence. Why is this ? Here 
is the glorious paradox of life. We live only as we 
die. The moment we cease dying, we cease living. 
All our life is produced by the destruction of our 
bodies. No act can be performed except by the 
wearing away of a muscle. No thought can be 
evolved except at the expense of the brain. Hence 
the necessity for food to supply the constant waste 
of the system,* and for sleep to give nature time to 
repair the losses of the day. Thus, also, we see why 
we feel exhausted at night and refreshed in the 
morning. 

the Common Scavenger. — God has no idlers in 
His world. Each atom has its use. There is not an 
extra particle in the universe. The mission of oxy- 
gen, so destructive in its action, is therefore essen- 
tial, that every waste substance may be collected 
and returned to the common stock, for use in nature's 
laboratory. In performing this general task, its uses 

* This food must be organic matter endowed with, potential energy 
treasured up in the plant. When it is transformed into flesh, perhaps 
made still more vital in the process, we have this power standing ready to 
be used again at our pleasure. When we will it, the O combines with the 
flesh and sets free the energy for us to apply. 



22 INORGANIC CHEMISTRY. 

are most important and necessary. It sweetens water, 
it keeps the avenues of the body open and unclogged,* 
it preserves the air wholesome. It becomes, in a word, 
the universal scavenger of nature. Every dark cellar 
of the city, every recess of the body, every nook and 
cranny of creation, finds it waiting ; and the instant 
an atom is exposed, the oxygen seizes upon it. A 
leaf falls, and its destruction forthwith commences. 
A tiny twig, far out at the end of a limb, dies, and 
the immediately begins its removal. A pile of de- 
caying vegetables, a heap of rubbish, the dead body 
of an animal, a fallen tree, the houses we build for 
our shelter, even the monuments erected above our 
final resting-place, are all gnawed upon by what we 
call the " insatiate tooth of time." It is only the 
constant corrosion of this destructive agent — oxygen. 
Consumption of 0. — Each adult uses daily 1\ lbs. 
of O. The combustion of 1 lb. of coal requires 
2f lbs. of : so that the ship which burns 1,000 
tons in crossing the ocean, takes out of the air 
2,666 tons of 0. Supposing the population of the 
earth to be 1,200,000,000, and each person to con- 
sume 1 lb. of. ; adding as much more to sustain 
fires ; twice as much for the wants of animals, and 
four times as much for the varied processes of de- 
cay, the daily consumption of reaches the enor- 
mous sum of 4,800,000 tons (Faraday). Yet the 
atmosphere contains over one quadrillion tons, and 



* Huxley very prettily calls O, in this connection, the " great sweeper " 
of the body, since it lays hold of all the waste matter of the system, and 
burning it up, removes it out of the way. 






OZONE. 



23 



even this vast aggregate is a mere fraction compared 
with the locked up in the ocean and the rock. 

Results if the Air were Undiluted 0. — The fire 
element would run riot every-where. Metal lamps 
would burn with the oil they contain. Our stoves 
would blaze with a shower of sparks. A fire once 
kindled would spread with ungovernable velocity, 
and a universal conflagration would quickly wrap 
the world in flame. 



Fig. 5. 



OZO N E. 

Ozone is an allotropic form of — i. e., a form in 
which the element itself is so changed as to have 
new properties. 

Source. — It is always perceived during the work- 
ing of an electric machine, and is then called "the 
electric smell." It is also said 
to have been noticed dur- 
ing thunder-showers, and is 
formed by evaporation and 
various processes of combus- 
tion. 

Preparation. — Place a 
freshly scraped stick of phos- 
phorus in a jar containing a 
little water, so that it shall 
be partly covered with the 
water. It will slowly oxidize, 
and the peculiar odor of ozone 

will soon be perceived in the jar. It may also be tested 
by a paper wet with a mixture of starch and po- 




Testing ozone. 



24 INORGANIC CHEMISTRY. 

tassium iodide (KI). The ozone sets free the iodine, 
which unites with the starch, forming blue iodide 
of starch.* At a temperature above that of boiling 
water, the ozone will turn back into 0. 

Properties. — Ozone is still more corrosive than 
oxygen. It tarnishes mercury, which oxygen does 
not attack at ordinary temperatures ; it bleaches 
powerfully, and it is a rapid disinfectant. A piece 
of tainted meat plunged into a jar of it is instantly 
deodorized, and it is probable that, even in minute 
quantities, this gas exercises a powerful influence in 
purifying the atmosphere. Ozone is condensed oxygen. 
Its molecule consists of three atoms of instead of 
two, as in ordinary oxygen. The change of oxygen 
into ozone may be thus represented : 
30 2 = 20 3 

Oxygen Ozone. 

WEIGHING AND MEASURING GASES. 

It is so much easier to measure the volume of a 
gas than it is to weigh it, that in practice the gas 
obtained by any reaction is usually measured and 
its 'amount or weight calculated from its volume. 
But since a given quantity of any gas by weight occu- 
pies a different volume at different temperatures and 
at different pressures, both temperature and pressure 
(height of barometer) at the time of measuring, have 
to be taken into account in making the calculation. 
The law for the change in volume produced by tem- 

* If a piece of the dry iodized paper be exposed upon a clear day to 
the open air of the country, in a few minutes it will assume a bluish tint. 
In cloudy, foggy weather, or in cities, this effect is rarely observed. 



WEIGHING AND MEASURING GASES. 25 

perature is : — a gas expands or contracts ^rs part of 
the volume it would have at 0°C, for every change 
of one degree centigrade in its temperature. Hence, 
if V be the volume of a gas measured at 0°C, and v 

the volume it would assume at t°C, v — V + -^z-o V. 
If v be the volume at i°C, the volume at 0°C, or 

ir 273 

V = *278+f 

The law for the effect of pressure is : — the volume 

of a gas varies inversely as the pressure. Hence, if 

the volume is V under pressure P and v under 

■xt t> j tt VP VP 

pressure p, V : v : : p : P; and V — -p- or v = . 

The pressure is stated in millimeters, and refers 
to the height of a column of mercury (barometer) 
which the pressure would sustain. 760 mm, is taken 
as the standard pressure, and 0°C. as the standard 
temperature. 

When the weight of a liter of any gas under 
standard conditions is known, the weight of any 
volume measured under any known conditions may 
be readily calculated. The steps of the calculation 
are : 1st. Find what the volume would be under 
standard conditions by means of the formulas given 
above. 2d. Multiply this result by the weight of one 
liter of the gas under these standard conditions. 

By means of our chemical equations we can find 
the weight of a gas which a given weight of the 
re-agents will produce (see p. 12). Now, the volume 
which this weight of gas will occupy under any 



26 INORGANIC CHEMISTRY. 

pressure and at any temperature, may be found by 
the following steps : — 1st. Divide the weight of the 
gas by the weight of our " standard " liter — this gives 
the volume under standard conditions. 2d. Find the 
volume at the given temperature and pressure by 
the use of the formulas. 

In this way we can find out exactly how many 
liters of a gas (e.g., 0), measured at the temperature 
of the room and under the existing atmospheric 
pressure, can be obtained from a given weight of the 
substance used for its production (e.g., KC10 3 ). 



PRACTICAL QUESTIONS. 

1. What becomes of the water that "dries up' 1 ? Of the wood that 
"burns up*'? Is there any destruction of the matter they contain? 

2. Where is the higher oxide formed, at the forge or in the pantry? 

3. Why is the blood red in the arteries, and dark in the veins? 

4. Do we need more O in winter than in summer? 

5. Which would starve sooner, a fat man or a lean one? 

6. How do teamsters warm themselves by slapping their hands together ? 

7. Could a person commit suicide by holding his breath? 

8. Why do we die when our breath is stopped? 

9. Why do we breathe so slowly when we sleep? 

10. How does a cold-blooded animal differ from a warm-blooded one? 

11. Why does not the body burn out like a candle? 

12. Do all parts of the body change alike? 

13. What objects would escape combustion if the air were undiluted O ? 

14. Why is it difficult to obtain O from the air? 

15. What weight of O can be obtained from 10 grams of HgO ? 

16. How much O can be obtained from 6 grams of KC10 3 ? 

17. How much KC10 3 would be needed to produce 2 kilograms of O? 

18. How much KC1 would be formed in preparing 1 kilogram of O ? 

19. Is it probable that all the elements are discovered? 

20. Is heat produced by oxidation? 

21. What is the difference between kinetic and potential energy? 

22. Why does running cause panting? 

23. How does O give us strength? 

24. Does the plant produce energy ? 

25. If we burn an organic body in a stove it gives off heat ; in the body 
it produces also motion. Explain. 



NITROGEN. 27 

26. Why does not blowing cold air on a fire with a bellows extinguish it » 

27. Why does blowing on a fire kindle it, and on a lighted lamp ex- 
tinguish it? 

28. Why can we not ignite hard coal with a match ? 

29. Why will an excess of coal put out a fire ? 

30. Could a light be frozen out, i.e., extinguished, by merely lowering 
the temperature? 

31. Why is it beneficial to stir a wood-fire, but not one of anthracite 
coal? 

32. Why will water put out a fire? 

33. What should we do if a person's clothes take fire? 

34. Ought the doors of a burning house to be thrown open ? 

35. How much O can be obtained from 100 grams of HgO? 

36. What would be the volume of the O of Question 35 under the 
standard conditions?* 

37. What would be the volume of the O at 12° C. and under a pressure 
of 740 mm. of mercury? 

38. What would be the volume of the O of Question 16 at 20° C. and 
750 mm. ? 

39. How much KC10 3 must be employed to make an amount of O 
which shall measure 100 liters at 18° C. and 760 mm. ? 



NITROGEN. 
Symbol, N ^tomic Weight, 14 Specific Gravity, 0,97, 

This gas is called nitrogen because it exists in 
niter. 

Occurrence. — N forms about 4 of the atmosphere, 
and is found abundantly in nitrates (e.g., saltpeter), 
ammonia, flesh, f and in such vegetables as the mush- 
room, cabbage, horse-radish, etc. It is an essential 
constituent of the valuable medicines, quinine and 
morphine, and of the potent poisons, prussic acid 
and strychnine. 

* The weight of a liter of O under standard pressure and at standard 
temperature is 1.43 gram. 

t Its compounds give to burnt hair and woolen their peculiar odor. 



28 



INORGANIC CHEMISTRY. 



Pig. 6. 




Preparing N. 



Preparation. — As the air consists almost exclusively 
of N and 0, the easiest method of obtaining the former 
gas is to remove the latter by employing it to oxidize 
some substance. The substance should be one which 
forms an oxide which is solid, liquid, or readily soluble, 

so that no gaseous prod- 
uct may be left mixed 
with the N. Place in the 
center of a deep dish of 
water a little stand sev- 
eral inches in height, on 
which a bit of phos- 
phorus may be laid and 
ignited. As the fumes 
of phosphorus pentoxide 
ascend, invert a receiver 
over the stand. The phosphorus will consume the 
of the air contained in the jar, leaving the N. After 
the jar has cooled it will be found that the N occu- 
pies f of the receiver. The jar will at first be filled 
with white fumes (P2O5), but they will be absorbed 
by the H 2 in a short time. 

Properties. — N is of an entirely negative charac- 
ter. It is colorless, odorless, and tasteless. It neither 
burns nor permits any thing else to burn. A candle 
will not burn in it, and a person can not breathe it 
alone and live, simply because it shuts off the life- 
giving 0. So will a person drown in H 2 not that 
the water poisons him, but because it fills his mouth, 
and shuts out the air. N has only a weak affinity 
for any of the elements. The instability of its com- 



NITROGEN. 29 

pounds is a striking peculiarity. It will unite with 
iodine, for example, but a brush with a feather, or 
a heavy step on the floor, will set it free.* 

Uses. — Relation of N to Organic Substances. — 
Four fifths of each breath that enters our lungs is 
N ; yet it conies out as it went in,f while that por- 
tion of the which remains behind performs its 
wonderful work within our bodies. About one sixth 
of our flesh is N, yet none of it comes from the air 
we breathe. We obtain all our supply from the lean 
meat and vegetables we eat. Plants breathe the air 
through the leaves — their lungs; yet they appro- 
priate but little of the N obtained in this way, and 
rely upon the ammonia and the nitric acid their 
roots absorb from the soil. N enters the stove with 
the — the latter unites with the fuel ; but the former, 
having no chemical attraction, passes out of the 
chimney. Even from a blast-furnace, where Fe melts 
like wax, N comes forth without the smell of fire 
upon it (p. 152). So inert is it, that it will not unite 
directly with any organic substance. We must all, 
animals and plants, depend upon finding it already 
combined in some chemical compound, and so appro- 
priate it to our use. But even then we hold it very 



* "Like a half -reclaimed gypsy from the wilds, it is ever seeking to be 
free again ; and not content with its own freedom, is ever tempting others, 
not of gypsy blood, to escape from thralldom. Like a bird of strong beak 
and broad wing, whose proper place is the sky, it opens the door of its 
aviary, and rouses and nutters the other and more peaceful birds, till they 
fly with it, although they soon part company.'' 1 — Edinburgh Review. 

t There is a constant though minute exhalation of 1ST through the pores 
of the skin. This small amount is perhaps absorbed in the lungs, but it is 
of no use to the body, so far as known. 



30 INORGANIC CHEMISTRY. 

loosely indeed. The tendency of flesh to decompose 
is largely owing to the instability of nitrogen com- 
pounds. 

Difference between N and 0.* — We see, now, how 
different N is from 0. The one is the conservative 
element, the other the radical. But notice the nice 
planning shown in the adaptation of the two to our 
wants. 0, alone, is too . active, and must be re- 
strained ; N, alone, is sluggish, and fit only to weaken 
a stronger element. Were the air undiluted 0, our 
life would be excited to a pitch of which we can 
scarcely dream, and would sweep through its fever- 
ish, burning course in a few days ; were it undiluted 
N we could not exist a moment. Thus we see that, 
separately, either element of the air would kill us, 
by excess and N by lack of action. 

and N combined. — A mixture of the active and 
the inert N gives us the golden mean. The now 
quietly burns the fuel in our stoves and keeps us 
warm ; combines with the oil in our lamps and gives 
us light ; acts upon the materials of our bodies and 
gives us warmth and strength ; cleanses the air and 
keeps it fresh and invigorating ; sweetens foul water 
and makes it wholesome ; works all around and within 
us a constant miracle, yet with such delicacy and 
quietness that we never perceive or think of it until 
we see it with the eye of science. 

Compounds. — Nitric Acid, HN0 3 . — Sources. — This 

* The difference between these two gases can be best illustrated by- 
having a jar of each, and rapidly passing a lighted candle from one to the 
other; the X will extinguish the flame, and the O relight the coal. By 
dexterous management, this may be repeated a score of times. 



NITROGEN. 



31 



compound of H, N, and can not be easily made by 
the direct union of its elements, on account of the 
inert character of N ; but compounds closely allied 
to it are formed in favorable soils by the decompo- 
sition of the waste products of animal life. These 
compounds contain a metal, usually K or Na, in place 
of the H, and are called nitrates — e.g., KN0 3 , potas- 
sium nitrate; NaN0 3 , sodium nitrate. 



Fig. 7. 




Preparing HN0 3 . 

Preparation. — Nitric acid is prepared by treating 
a nitrate with a stronger acid. Thus, if sulphuric 
acid (H 2 S0 4 ) and sodium nitrate be gently heated 
together in a retort, nitric acid will distil over and 
can be collected in a receiver, cooled by dripping 
water. 

The chemical reaction may be represented thus: 
2NaN0 3 + H 2 S0 4 = Na 2 S0 4 + 2HN0 3 . 

Properties. — It is an intensely corrosive, poisonous 
liquid. When pure, it is colorless ; but as sold, it has 
commonly a golden tint from the presence of an 



32 INORGANIC CHEMISTRY. 

oxide of N, produced by the decomposing action of 
the light. In strength it is next to H 2 S0 4 . It dis- 
solves most metals with the formation of nitrates. 
It was formerly called aqua fortis, or strong water. 
It stains wood, the skin, etc., a bright yellow. Both 
nitric acid and nitrates give up their readily, and 
hence are powerful oxidizing agents.* 

Uses. — HN0 3 is employed in dying silk yellow, in 
making gun-cotton, nitro-glycerin, and other explo- 
sives, and in surgery for cauterizing the flesh. In 
combination with HC1, it forms aqua regia, the usual 
solvent of Au. It etches the lines in copper-plate 
engraving, and the beautiful designs on the blades 
of razors, swords, etc. The process is very simple : 
the surface is covered with a varnish impervious to 
the acid, and the desired figure is then sketched 
in the varnish with a needle. The HN0 3 being 
poured on, dissolves the metal in the delicate lines 
thus laid bare. 

Nitrous Oxide, N 2 0. — Preparation. — This gas is 
made by heating ammonium nitrate (NH 4 N0 3 ), which 
decomposes into 2H 2 and N 2 0. (See p. 33.) 

Properties. — N 2 is a colorless, transparent gas 

* The following experiments illustrate this property: 

1. Mix equal parts of strong HN0 3 and H 2 SO*. Place a little oil of 
turpentine in a cup out-of-doors, and pour the mixture upon it at arm's 
length. The turpentine will burn with almost explosive violence. 

2. Pour dilute KN T 3 upon bits of tin. Dense, red fumes (NO a , nitric 
peroxide) will pass off, and the Sn will be converted into a white oxide, 
which furnishes what is termed putty powder. 

3. Throw crystals of any nitrate on red-hot coals. They will deflagrate 
on account of the O which they give up to the fire. 

4. SoaK a strip of blotting-paper in a solution of niter. It will form 
"touch-paper," and when lighted will only smolder. 



NITROGEN. 



33 



Fig. 8. 




Preparing N 2 0. 



with a faintly sweetish taste and smell. It is some- 
what soluble in water, so that there is some loss 
when it is collected over water. It supports com- 
bustion nearly as 
well as 0, and many 
of the experiments 
ordinarily per- 
formed with 
will be almost as 
brilliant with N 2 0. 
If breathed for a 
short time, it pro- 
duces a peculiar 
kind of intoxica- 
tion, often attended 

with uncontrollable laughter, and hence it has re- 
ceived the popular name of laughing gas. The effect 
soon passes off. If taken for a longer time, it causes 
insensibility, and is therefore valuable as an anaes- 
thetic in minor surgical operations, as in pulling teeth. 

Nitric Oxide, NO. — Preparation. — This gas may be 
prepared by the action of dilute HN0 3 on copper 
clippings. The flask (a, Fig. 9) will soon be filled 
with red fumes, but a colorless gas will collect in 
the jar over water. At the conclusion of the process, 
the flask will contain a deep blue solution of copper 
nitrate (Cu2N0 3 ). By filtering and evaporating, the 
beautiful crystals of this salt may be obtained. 

There are two changes involved in the reaction ; 
in the first, copper nitrate is formed and H set free : 
Cu + 2HN0 3 = Cu2N0 3 + 2H ; 



34 



INORGANIC CHEMISTRY. 



and then the H is oxidized by the nitric acid with 
the production of water and NO : 

2HN0 3 + 6H = 4H 2 + 2N0. 



Fig. 9. 




Preparing NO. 

Properties. — NO is a colorless, irrespirable gas with 
a disagreeable odor. It does not burn, nor does it 
support combustion, although it contains twice as 
much as N 2 0. This shows that the is held more 
firmly than in the latter gas. Its remarkable prop- 
erty is its affinity for 0. Let a bubble escape into 
the air, and red fumes of nitric peroxide (N0 2 ) will 
be formed.* 



* This may be illustrated still more prettily by the following experi- 
ment :— Fill a small jar with water colored blue by litmus solution, and 
pass up into it sufficient NO to occupy about one third of the bottle ; the 
litmus will not change in color. Now allow a few bubbles of O to rise into 
the NO ; deep red fumes will be formed, which will quickly dissolve, and 
the blue solution become red. If both the O and the NO be pure, it is 
possible, by cautiously adding O, to cause a complete absorption of both 
gases. If common air were used instead of O, only N would then remain 
in the jar. 



NITROGEN. 



35 



Ammonia, NH 3 .— Source.— This gas was formerly 
called hartshorn, because in England it was made 
from the horns of the hart. It received the name 
ammonia, by which it is now more generally known, 
from the temple of Jupiter Ammon, near which sal- 
ammoniac, one of its compounds, was once manu- 
factured. The aqaa am- 
monia of the shops, 
which is merely a strong 
solution of the gas in 
H 2 0, is obtained from 
the incidental products 
of the gas-works in large 
quantities. (See p. 72.) 
Its pungent odor can 
often be detected near 
decaying vegetable and 
animal matter. 

Preparation. — NH 3 is 
ordinarily prepared by 
heating sal - ammoniac 
with lime.* The reac- 
tion may be represented as follows : 

2NH 4 C1 + CaO = 2NH 3 + H 2 + CaCl 2 . 
It is also conveniently obtained for experiments by 
gently heating aqua ammonia. 

Properties.— NH 3 is a colorless gas, having a pecul- 
iar pungent and suffocating odor, and a caustic taste. 

* This may be illustrated by simply mixing in a cup some powdered sal- 
ammoniac (ammonium chloride) and lime (calcium oxide), when the ammo- 
nia may be detected by its odor, and the bluing of moist red litmus-paper. 




Preparing XH 3 . 



36 IKOKGANIC CHEMISTRY. 

It can be readily condensed to a liquid by cold or 
pressure. When liquefied by pressure, it passes rap- 
idly back into the gaseous state when the pressure 
is removed, and in doing so, absorbs so much heat 

Fig. 11. 



Absorption of NH 3 in water. 

that water can be frozen.* NH 3 will not support 
combustion, nor will it burn in air under ordinary 
conditions ; but it burns in with a pale yellow 
flame. It dissolves very freely in water, \ forming a 

* Carre's machine for making artificial ice makes use of these facts. 
For a description of this see Roscoe and Schorlemmer, under Ammonia. 

t Heat a little aqua ammonia in a flask. Dry the vapor and collect in 
an inverted bottle, for which a cork and tube, with the inner extremity 
drawn to a fine point over the spirit lamp, has been provided. Insert 
the cork, and then plunge the bottle into a vessel of water. The water 
which passes in first will absorb the gas so quickly as to make a par- 
tial vacuum, into which the water will rush so violently as to produce a 
miniature fountain. If the water is colored with a little red litmus, it 
will turn blue as it enters the bottle. 



NITROGEN. 



37 



solution which smells strongly of FlG - 12 - 

the gas, and from which it can be 
all driven off by heat. 

Nascent State.— Though N and H, 
if mixed in a receiver, will not unite 
chemically without the agency of 
heat or electricity, in the decomposi- 
tion of organic substances containing 
N and H, these elements often combine 
to form N H 3 . Other elements show a 
very similar difference in chemical 
activity. It is therefore supposed that 
elements, in the act of being set free 
from their compounds, have a peculiar chemical ac- 
tivity, and are then said to be in the " nascent state." 




NH 3 burning in O. 



PRACTICAL QUESTIONS. 

1. How could you detect any free O in a jar of N? 

2. How would you remove the product of the test? 

3. In the experiment shown in Pig. 9, why is the gas red in the flask, 
but colorless when it bubbles up into the jar? 

4. How much NH 3 can be obtained from 3 grams of sal-ammoniac? 

5. What will be the volume of the ]STH 3 at 20° C. and 770 mm. ? 

6. How much H 2 will be formed in the process? 

7. How much CaO will be needed ? 

8. How much N 2 can be made from 1 gram of ammonium nitrate? 

9. How much nitric acid can be formed from 50 kilos of sodium nitrate 
0STaNO 3 ) ? 

10. What causes flesh to decompose so much more easily than wood? 

11. If a tuft of hair be heated in a test tube, the liquid formed will 
turn red litmus paper blue. Explain. 

12. Why should care be used in opening a bottle of strong NH 3 in a 
warm room? 

13. What weight of X is there in 10 grams of HNO s ? 

14. How much sal-ammoniac would be required to make 20 liters of 
NH 3 measured at 25° C. and 744 mm. ? 

15. What is the difference between liquid ammonia and liquor ammonise ? 



38 



INORGANIC CHEMISTRY. 






Fig. 13. 



HYDROGEN. 
Symbol, H Atomic Weight, 1 Specific Gravity, ,069. 

Hydrogen means literally a generator of water. 
Occurrence. — H forms one ninth the weight of 
water, and is a constituent of all animal and vegeta- 
ble substances. 

Preparation. — It may 
be obtained from water by 
means of the electric cur- 
rent, or by the action of 
certain metals. If an elec- 
tric current be led through 
acidulated water, H is given 
off at the negative pole 
and at the positive pole. 
If a small piece of sodiur 
is thrown on water, it 
melts and rolls over its surface like a tiny silver 
ball. If the water be heated, the ball bursts into a 
bright yellow blaze. If potassium 
be used instead of sodium, the H 
catches fire at once, even on cold 
water, and burns with some vola- 
tilized K, which tinges the flame 
with a beautiful purple tint.* If 
the water be examined after the action is over, it 
is found to feel soapy, to turn red litmus paper blue, 




Preparing hydrogen. 



Fig. 14. 



£fr 



K on H a O. 



* Cut the metal in small pieces and cover it with wire gauze, since the 
melted globule bursts at the close of the experiment. 



HYDROGEN. 39 

and to leave, on evaporation, a white substance. 
This white substance is KOH or NaOH, potassium or 
sodium hydroxide. The formation of this substance 
and of H by the action of Na on water is represented 
as follows : 

H 2 + Na = NaOH + H. 

The H made in this way may be collected in an 
inverted test tube full of water by imprisoning the 
globule of Na in a cage of wire gauze beneath the 
mouth of the tube. 

H is usually prepared from sulphuric acid (H 2 S0 4 ) 
by the action of zinc. The reaction is as follows : 

H 2 S0 4 + Zn + H 2 = ZnS0 4 + H 2 + 2H. 

The ZnS0 4 (zinc sulphate) is contained in the solu- 
tion which remains, and may be obtained in crystals 
by evaporating off the water. With strong H 2 S0 4 
other reactions occur. 

Properties.— H prepared in this manner has a dis- 
agreeable odor, from impurities which it contains.* 
When pure, it is, like 0, colorless, transparent, and 
odorless. It is the lightest of all bodies, being four- 
teen and a half times lighter than air, and sixteen 
times lighter than 0. It is not poisonous, although, 
like N, it will destroy life by shutting out the life- 
sustainer, 0. When inhaled, it gives the voice a 
ludicrously shrill tone. It can be breathed for a few 
moments with impunity, if it be first purified. Owing 
to its lightness, it passes out of the lungs again 

* This odor can be removed by causing it to bubble through, a solution 
of potassium permanganate. (See Fig. 13.) 



40 



INORGANIC CHEMISTRY. 



Fig. 15. 




Candle in H. 



directly. Its levity suggested its use for filling bal- 
loons,* and it has been employed for that purpose ; 
but coal gas, which contains much H 
and is cheaper, is now preferred. 

Combustion of H. — A lighted candle, 
plunged into an inverted jar of H, is 
extinguished, while the gas 
itself takes fire and burns 
with an almost invisible 
flame. One atom of the 
of the air unites with two 
atoms of the H, and the 
product of the combustion is H 2 0, which 
may be condensed on a cold tumbler, held 
over a jet of the burning gas. (See 
Fig. 17.) The apparatus shown in Fig. 16 
is a more simple means of illustrating 
the properties of H.f 

Mixed Gases. — A mixture of two 
parts, by measure, of H, with one part of 0, or 
five parts of common air, when ignited, will explode 
violently.^ The heat generated by the union of H 




* We read in accounts of fetes at Paris, of balloons ingeniously made 
to represent various animals, so that aerial hunts are devised. The ani- 
mals, however, persistently insist upon ascending with their feet up— a 
circumstance productive of great mirth in the crowd of spectators. 

t Let the gas escape a few moments before lighting it, so that the air 
may be driven out of the flask. 

t The H gun— which is simply a tin tube, closed at one end, and pro- 
vided with a cork at the other, having a priming-hole at the side— is used 
to illustrate this fact. It may be filled over the jet of the evolution flask 
(Fig. 16) when that is not ignited. The gas is allowed to pass in until 
the gun is about a fifth full, as nearly as one can guess, when the gun is 
removed and the gases ignited at the priming-hole. 



HYDROGEN. 
Fig. 17. 



41 




H a O formed by burning H. 

and causes the H 2 which is formed to appear in 
the state of steam. Immediately after, the steam 

Fig. 18. 




H%i!ife 



Transferring gases. 

being condensed, a vacuum is produced and the par- 
ticles of air rushing in to fill the empty space, by 



42 



INORGANIC CHEMISTRY. 



Pig. 19. 



their collision against each other, cause the deafen- 
ing sound. While the detonation is so great, the 
force is slight, as may be shown by exploding, in the 
hand, soap-bubbles blown with the gases. H and 
may be mingled in the right proportion for combus- 
tion, and kept for years without any change taking 
place. The two gases remain quietly together, with 
no manifestation of their chemical affinity, until sud- 
denly, at the contact of the merest spark of fire, 
they rush together with a crash like thunder, and 
uniting, form the bland, passive liquid — water. 

Action of Spongy Platinum. — A piece of spongy 
platinum placed in a jet of H will ignite it. This 
curious effect seems to be produced 
in the following way : The H and the 
of the air are brought so closely 
together in its minute pores that they 
unite, and the heat thus generated 
sets fire to the gas. This action is 
nicely shown by the instrument repre- 
sented in Fig. 19. It was formerly 
used by chemists as a convenient way 
of obtaining a light in the laboratory. 
Friction matches have superseded this 
ingenious invention. 

Heat of Burning H. — A hydrogen flame gives little 
light, but great heat. In H and 0, existing as gases, 
there is stored a vast amount of potential energy. 

* Z is a piece of zinc suspended in a solution of dilute H 2 S0 4 . At 
the top is a stop-cock, by turning which the gas is allowed to pass out 
from the receiver /. It strikes upon a piece of spongy platinum, and ignites 
with a slight explosion. 




Dobereinefs Lamp* 



HYDROGEN. 



43 



Pig. 20. 



("Physics," pp. 36, 3 7.) When they unite by chem- 
ical affinity, this energy is transformed chiefly into 
heat. In the union 
of 8 grams of and 
one gram of H, suffi- 
cient heat is evolved 
to raise 34,462 
grams of water from 
0° to 1° centigrade ; 
and this heat is 
sufficient to do the 
amount of work 
represented by lift- 
ing 14,612 kilo- 
grams a meter high. 
The Chemical 
Harmonica.* — The 
vibration of a col- 
umn of air can be 
illustrated by sim- 
ply holding a long 
glass tube, by means 
of a suitable clamp, 




* Another illustration of singing hydrogen may be represented in the 
following manner: Make a jar of heavy tin, in the form of a double cone, 
twelve inches long and four inches in diameter. At one apex fit a nozzle 
and cork; at the other, make several minute openings. Cover the holes 
with sealing-wax, and draw the cork ; then fill the jar with H, and replace 
the cork. When ready for use, hold the jar in a vertical position, remove 
the wax from at least one orifice, ignite the H at that point, and draw the 
cork. Still hold the jar quietly, and in a minute or two the tiny jet of H 
will begin to sing like a swarm of mosquitoes, buzzing and humming in a 
most aggravating way until, unexpectedly, the fitful music ends in a loud 
explosion. 



44 IKORGANIC CHEMISTRY. 

over a minute jet of burning H. At first no effect 
will be produced ; but as we slowly introduce the 
jet farther and farther into the tube, a faint sound 
is heard, apparently in the far-off distance. It grad- 
ually strengthens, and finally bursts into a shrill, 
continuous, musical note — the key-note of the heated 
column of air within the tube. The flame rises and 
falls in rapid succession without ever becoming 
quite extinguished, as may be seen by looking at 
its image in a revolving mirror ; and the succes- 
sion of minute collapses of the body of air around 
it is regulated by the length of the pipe. Let us 
now place the tube at a point where no clapping 
of hands or unusual sound will start it into song. 
Let various tones be produced from a violin, and 
we shall find the flame responding only to that 
tone which is the key-note of the tube, or its octave. 
The violin player will have perfect control of this 
musical flame, and can start, stop, or throw it into 
violent convulsions, even across a large hall. Tubes 
of different sizes and lengths will give tones of 
diverse character and pitch.* The waves of sound 
from the instrument augmenting or interfering 
with those in the tube probably produce these phe- 
nomena. 



* The singing of the hydrogen flame may be illustrated by holding 
large tubes of any kind, over the flame of the evolution flask. Jets of dif- 
ferent sizes may be made by drawing out glass tubing over the spirit-lamp. 
Attaching a jet, by india-rubber tubing, to the nozzle of a common gas 
pipe, we may utilize the H in coal gas, and at the same time secure a 
brighter flame and regulate the pressure at will. The singing may be pro- 
duced even if the jet and tube be horizontal or inverted. 



WATER. 



45 



Fig. 21. 



WAT E R. 

The composition of H 2 is proved by analysis and 
synthesis— i. e., by separating the compound into its 
elements, and by combining the elements to produce 
the compound. We can analyze it in the manner 
already shown in preparing H by passing through it 
an electric current. In the syn- 
thetic method, we mix the two 
gases and unite them as we 
have before or by an electric 
spark. Both methods agree in 
proving that water is composed 
of two volumes of H to one 
of 0. But is sixteen times 
heavier than H, volume for vol- 
ume, and hence the composition 
of water by weight is 2:16 
or 1 : 8. This fact is expressed 
in its formula H 2 0. The black- 
smith decomposes water when 
he sprinkles it on the hot coals 
in his forge. The H burns with a pale flame, while 
the increases the combustion. Thus, in a fire, if the 
engines throw on too little water, it may be decom- 
posed, and add to the fury of the flame.* To "set 

* "No more heat is produced by the action of the H 2 0, but it is in a 
more available form for communicating heat. The steam in contact with 
incandescent charcoal is decomposed— the O going to the C to form C0 2 , 
and the H being set free. If the C is abundant, and the heat high, the 
COo is also decomposed, and double its volume of CO formed. The inflam- 
mable gases, H and CO, mingled with the hydrocarbons always produced, 
are ignited, making the billows of flame which sweep over a burning 
building."^. P. Sharples. 




Analysis of water. 



46 INOEGANIC CHEMISTRY. 

the North River on fire " is only a poetical exag- 
geration. 

The quantity of electricity required to decompose 
a single grain of water is estimated to be equal to 
that in a flash of lightning. The enormous power 
necessary to tear these two elements from each 
other shows the wonderful strength of chemical at- 
traction.* We thus see, that in a tiny drop of dew 
there slumbers the latent power of a thunder-bolt. 

Water in the Animal World. — The abundance of 
water very forcibly attracts the attention. It com- 
poses perhaps four fifths of our flesh and blood. 
Man has been facetiously described as twelve pounds 
of solid matter wet up in six pails of water. All 
plumpness of flesh, and fairness of the cheek, are 
given by the juices of the system. A few ounces of 
water and a little charcoal constitute the principal 
chemical difference between the round, rosy face of 
sixteen, and the wrinkled, withered features of three- 
score and ten. To supply the constant demand of 
the system for water, each adult, in active exercise, 
needs about three pints per day, or over half a ton 
annually. (See " Physiology," p. 220.) When we pass 
to lower orders of animals, we find this liquid still 
more abundant. Sunfishes are little more than or- 
ganized water. Professor Agassiz analyzed one found 
off the coast of Massachusetts, which weighed thirty 
pounds, and obtained only half an ounce of dried 
flesh. Indeed, an entire class of animals (hydrozoa), 

* The power needed to separate them "becomes latent in the gases as a 
potential energy, and when they are burned at any time will be set free as 
sensible heat— a form of kinetic energy. 



WATER. 47 

to which belong the jelly-fish, medusa, etc., is com- 
posed of only ten parts in a thousand of solid matter. 
(See " Zoology," p. 2 69.) 

Water in the Vegetable World. — In the vegetable 
world we find it abundant. Air-dried wood contains 
40 per cent, of H 2 0; bread is 3 7 per cent, water; 
and of the potatoes and turnips cooked for our din- 
ner, it comprises 75 per cent, of one and 91 of the 
other. The following table shows the proportion in 
common vegetables, fruits, and meats : 



Mutton 76 

Beef 72 

Veal 78 

Pork 72 

Eggs . ... .74 



Oysters 90 

Salmon 74 

Apples 85 

Carrots 88 



Beets 90 

Cabbage 80 

Cucumbers ... .96 
Melons 90 



Water in the Mineral World. — Bodies in which 
the water is chemically combined in definite propor- 
tions, are often called hydrates. In the image which 
the Italian peddler carries through our streets for 
sale, there is nearly one pound of H 2 to every four 
pounds of plaster of Paris. One third of the weight of 
any ordinary soil is this same liquid. In some bodies 
which are capable of crystallizing, it seems to deter- 
mine the form and general appearance, and is called 
"the water of crystallization." If we heat blue vitriol, 
its water of crystallization will be driven off, and it 
will lose its color and become white like flour.* A few 
drops of H 2 will restore the blue. If we expel the 

* This may be easily shown by filling the bowl of a clay tobacco-pipe 
with crystals of the salt, and heating them over a lamp or in the fire until 
the water of crystallization is expelled. Alum may be made anhydrous in 
the same way. 



48 INORGANIC CHEMISTRY. 

water from alum, it will puff up, and the transparent 
crystals will dry into an incoherent mass. Many salts 
effloresce, i.e., part with their water of crystallization on 
exposure to the air, and crumble into a white powder. 

Water as a Solvent. — Water, having no taste, 
color, or odor itself, is perfectly adapted to be the 
general solvent. It becomes at pleasure sweet, sour, 
salt, bitter, nauseous, and even poisonous. Had water 
any taste, the whole art of cookery would be changed, 
since each substance would partake of the one uni- 
versal watery flavor. 

Pure Water. — Rain-water, caught after the air is 
thoroughly cleansed by previous showers, and at a 
distance from the smoke of cities, is the purest 
natural water known. It is tasteless, yet its insi- 
pidity makes it seem to us very ill-flavored indeed. 
We have become so accustomed to the taste of the 
impurities in water, that they have become to us 
tests of its sweetness and pleasantness. 

River- Water, though it may have less mineral 
matter than spring-water, is often unfitted for drink- 
ing on account of the organic matter it contains. 
Happily, running water has in itself a certain puri- 
fying power, owing to the air which it holds in solu- 
tion ; so that organic substances are burned in it as 
certainly as they would be in a stove. Still, in order 
to avoid any danger, river-water should be filtered 
through charcoal or sand before using.* 

* A weak solution of potassium permanganate is an excellent test of the 
presence of organic matter. Place the water to be examined in a glass, 
and add a few drops of sulphuric acid and a little permanganate ; if or- 
ganic matter is present, the violet permanganate solution is decolorized. 



WATER. 49 

Hard Water. — As water percolates through the 
soil into our wells, it dissolves the various mineral 
matters characteristic of the locality.* The most 
abundant of these are lime, salt, and magnesia. 
The former produces a fur or coating on the bottom 
of our tea-kettles, if we live in a limestone region. 
When we put soap in such water, it curdles — i. e., it 
unites with the lime (CaO), forming a new, or lime 
soap, which is insoluble in H 2 0. H 2 containing an 
excess of mineral matter, is unwholesome ; yet it is 
probable that the sparkling hard waters of the lime- 
stone districts are relished, not only because they are 
pleasant to the eye and agreeable to the taste, but 
on account of some hygienic properties in the excess 
of CO 2 they contain, and possibly because the CaO 
acts medicinally on the system, f 

It is a fact worthy of note that lime and oxide 
of iron, which are frequently found in H 2 0, the lat- 
ter generally in minute quantities, are both health- 
ful ; while the oxides of the other metals are poison- 
ous. Were zinc or barium, for instance, as common 



* Most of the water in our world is unwholesome for drinking purposes. 
On the great ocean, whose volume is more than thirty times that of all 
the land above sea-level, there is 

"Water, water every- where 
And not a drop to drink. " 

+ The French authorities are so well satisfied of the superiority of hard 
water, that they pass by that of the sandy plains, near Paris, and go far 
away to the chalk hills of Champagne, where they find water even harder 
than that of London ; giving as a reason for the preference that more of 
the conscripts from the soft- water districts are rejected on account of the 
want of strength of muscle, than from the hard-water districts. They 
conclude that calcareous matter is favorable to the formation of the tissues. 
No positive decision on this point is possible. 



50 INORGAJSTIC CHEMISTRY. 

near our homes as iron or calcium, wholesome drink- 
ing water would be rarely, if ever, found. 

Sea- Water. — The most abundant mineral in the 
ocean is common salt. Yet sea-water contains traces 
of every substance soluble in water, which has been 
washed into the sea from the surface of the conti- 
nents during all the ages of the past. Its saline 
constituents are now in the proportion of about one 
part in twenty-eight. This amount may be slowly 
increasing, as the water which evaporates from the 
surface is pure. In this way, the water of the Salt 
Lake has become a strong brine, more than one fifth 
of its whole weight consisting of saline matter. This 
condition would soon disappear if an outlet were 
provided. 

Water Atmosphere. — As the world of waters is 
inhabited, it also has its atmosphere.* Inasmuch as 
the H 2 dilutes the in part, it does not need so 
much N as the common air. It is accordingly com- 
posed of over one third instead of only one fifth. 
The air, so rich in 0, thus absorbed by the water, 
gives to it life and briskness. If it be expelled by 
boiling, the water tastes flat and insipid. 

Paradoxes of Water. — "Cold contracts," is the law 
of physics ; but as H 2 cools, it obeys this general law 
only as far as 39° F. (or 4°C). Then it slowly ex- 
pands, cooling down to 32°, its freezing point, when 
its crystals suddenly dart out at angles to each other, 

* Eish inhale O through the fine silky filaments of their gills. When a 
fish is drawn out of H 2 0, these dry up, and it is unable to breathe, although 
it is in a more plentiful atmosphere than it is accustomed to enjoy. 



WATER. 51 

and thus, increasing in size about one twelfth, it con- 
geals to ice. Ice is therefore lighter than water, and 
so swims on top ; otherwise, in severe winters, our 
northern rivers would freeze solid, killing the fish and 
aquatic plants. The longest summer could not melt 
such an immense mass of ice. But now the blanket 
that Nature weaves over the rivers and ponds pre- 
vents the water beneath from reaching the freezing 
point. We give to water such contradictory terms 
as "hard" and "soft," "fresh" and "salt." H 2 seems 
the most yielding of substances, yet the swimmer 
who falls on his face, instead of striking head fore- 
most, appreciates the mistake, and we could drive a 
nail into a solid cube of steel almost as easily as into 
a hollow one perfectly filled with H 2 0. H is the light- 
est substance known, and is an invisible gas ; yet 
they unite and form a liquid whose weight we have 
often experienced, and a solid which makes a pave- 
ment hard like granite. H burns readily and, when 
mixed with 0, explodes most fearfully ; supports 
combustion brilliantly — yet the two combined are 
used to extinguish fires. H or in excess would 
destroy life ; H 2 is so essential to it that thirst 
causes a lingering, painful death. 

Uses of Water. — The uses of H 2 are as diverse 
as they are practical. Its properties fit it for a won- 
derful variety of operations in nature. Its office is 
not merely to moisten our lips on a hot day, to make 
a cup of coffee, to lay the dust in the street, and to 
sprinkle our gardens ; it has grander and more pro- 
found uses than any of these. Water is the common 



52 INORGANIC CHEMISTRY. 

carrier of creation. It dissolves the elements of the 
soil and, climbing as sap up through the delicate 
capillary tubes of the plant, furnishes the leaf with 
the materials of its growth. It flows through the 
body as blood, floating to every part of the system 
the life-sustaining 0, and the food necessary for re- 
pairs and for building up the various parts of the 
"house we live in." It comes from the clouds as rain, 
bringing to us warmth from the ocean and temper- 
ing our northern climate, while in spring it floats 
the ice of our rivers and lakes away to warmer seas 
to be melted. It washes down the mountain side, 
leveling its lofty summit and bearing mineral mat- 
ter to fertilize the valley beneath. It propels water- 
wheels, working forges and mills, and thus becomes 
the grand motive-power of the arts and manufact- 
ures. It flows to the sea, bearing on its bosom ships 
conducting the commerce of the world. It passes 
through the arid sands, and the desert forthwith 
buds and blossoms as the rose. It limits the bounds 
. of fertility, decides the founding of cities, and directs 
the flow of trade and wealth. 



PRACTICAL QUESTIONS. 

1. Why, in filling the hydrogen gun, do we use 5 parts of common air 
to 2 of H, and only 1 part of O to 2 of H ? 

2. Why are coal cinders often moistened with H 2 before using? 

3. What injury may be done by throwing a small quantity of H 2 on 
a fire? 

4. Why does the hardness of water vary in different localities? 

5. What causes the variety of minerals in the ocean? Is the quantity 
increasing ? 

6. Is there not a compensation in the sea-plants, fish, etc., which are 
washed back on the land ? 



CARBON. 53 

7. Since "all the rivers flow to the sea," why is it not full? 

8. What is the cause of the tonic influence of the sea-breeze? 

9. When fish are taken out of the water and thus brought into a more 
abundant atmosphere, why do they die? 

10. Do all fish die when brought on land? 

11. What weight of water i3 there in a hundredweight of sodium sul- 
phate CNa a S0 4 , 10H 2 O), or Glauber's salt? 

12. What weight of water in a ton of alum (KA12S0 4 , 12H.,0)? 

13. How does the air purify running water? 

14. What is the action of potassium permanganate as a disinfectant? 

15. What weight of H can be obtained from a liter of water? 

16. How much Zn must be employed to obtain 100 grams of H from 
H a S0 4 ? 

17. A liter of H under standard conditions weighs 0.089G gram. What 
volume of H at 10° C. and 738 mm. can be obtained from H.S0 4 by the 
action of 8 kilos of Zn ? 

18. How much KC10 3 would be required to evolve sufficient O to burn 
the H produced by the decomposition of 2 grams of H 2 ? 

19. How much O would be required to oxidize the metallic Cu which 
could be reduced from its oxide by passing over it, when white-hot, 20 
grams of H gas? 

20. How much O would be required to oxidize the metallic Fe which 
could be reduced in the same manner by 10 grams of H gas? 

21. Why are rose-balloons so buoyant? 

22. How much H must be burned to produce a ton of water? 



CARBON. 

Symbol, C, Atomic Weight, 12, Specific Gravity of Diamond, 3,5 to 3.6, 

Occurrence. — C is one of the most abundant sub- 
stances in nature, forming nearly one half of the 
entire vegetable kingdom, and being a prominent 
constituent of lime-stone, corals, marble, magnesian 
rocks, etc. We find it uncombined in two distinct 
forms or allotropic conditions — viz., the diamond and 
graphite. 

The Diamond is pure carbon crystallized. It is 
the hardest of all known substances, scratches all 



54 INORGANIC CHEMISTRY. 

other minerals and gems, and can be cut only by 
its own dust. It is infusible, but will burn at a high 
temperature. Nearly all the diamonds of commerce 
now come from the Cape of Good Hope. India, 
Borneo, and Brazil had valuable mines, and in 1858 
Brazil furnished 120,000 carats.* Diamonds usually 
occur crystallized in the form of the regular octahe- 
dron or forms derived from it belonging to the reg- 
ular system of crystallography. They are of various 
tints, though often colorless and perfectly transparent. 
The last are most highly esteemed and, from their 
resemblance to a drop of clear spring-water, are 
called diamonds of the " first water." They are ex- 
ceedingly brittle, and valuable gems are said to have 
been broken by simply falling to the floor. Nothing 
definite is known concerning the origin of this gem.f 



* A carat is a little less than 4 grains Troy. The term is derived from 
the name of a bean, which, when dried, was formerly used in weighing by 
the diamond merchants in India. 

t Although the diamond is simply pure carbon crystallized, all attempts 
to make it have been until recently unsuccessful. A few years ago, it was 
discovered that artificial diamonds having all the characteristics of the nat- 
ural stones could be formed ; but thus far, all that have been made are very 
minute and interesting only from a scientific point of view. The value of 
the diamond varies with the market ; the general rule is as follows : a gem 
ready for setting, of one carat weight, is worth $150 to $180 ; beyond this 
size, the estimated value increases according to the square of the weight, 
but in case of large stones is generally much less than that amount, 
although rare beauty or size may greatly enhance the price. The Kohi- 
noor (mountain of light, now among the crown jewels of England) weighs 
103 carats, yet is valued at $10,000,000. Owing to the discovery of many 
large diamonds in South Africa, the value of such stones has much decreased 
of late. The smaller ones, however, are becoming more expensive on 
account of the greater demand for them. The South African diamonds are 
seldom colorless, having generally a yellowish tint. Paste diamonds are 
now made in Paris, which are so perfect an imitation that only experts 
can distinguish them from the real gems. 




CAKBON. 55 

The Diamond is ground by means of its own 
powder. Being fitted to the end of a stick or handle, 
it is pressed down firmly against the face of a rapidly 
revolving wheel, covered with diamond-dust and oil. 
This, by its friction, removes the exposed edge and 
forms a facet of the gem. There 
are three forms of cutting — the Fro. 22 - 

brilliant, the rose, and the table. 
The brilliant has a flat surface on 
the top, with facets at the side, T u bnmant. The rose. 
and also below, the latter termi- 
nating in a point, so arranged as to refract the light 
most brilliantly. This form shows the gem to the 
best advantage, but is used only in large, thick 
stones, as it sacrifices nearly half the weight in cut- 
ting. The rose is flat beneath, while the upper sur- 
face is ground into triangular facets, terminating at 
a common vertex. The table form is employed for 
thin specimens, which are merely ornamented by 
small facets on the edge. The diamond is valued 
not alone for its rarity and high refractive power, 
by which it flashes such vivid and brilliant colors, 
but also for its mechanical uses. For cutting glass, 
the curved edges of the natural crystal are used. 

Graphite or Plumbago is also called black-lead, 
because on paper it makes a shining mark like lead. 
It is found at Ticonderoga, N. Y., Brandon, Vt, 
Sturbridge, Mass., and in Germany, South Siberia, 
Ceylon, and Australia. 

Uses.— A chief use is for pencils. For this pur- 
pose a mixture of powdered graphite and carefully 



56 INORGANIC CHEMISTRY. 

washed clay is employed.* Though graphite seems 
very soft, yet its particles are extremely hard and 
the saws used in cutting it soon wear out. We no- 
tice this property in sharpening a pencil with a 
knife. Graphite mixed with clay is made into black- 
lead crucibles. These are the most refractory known 
and are used for melting gold and silver. It is also 
sold as " British luster," "carburet of iron," "stove 
polish," etc., which are employed for blacking stoves 
and protecting iron from rusting. 

Amorphous Carbon. — This name is given to all 
modifications of carbon which are not diamond or 
graphite. The term amorphous means without crys- 
talline form. Under this head are included lamp- 
black, charcoal, coke, gas-carbon, animal charcoal, 
and coal. 

Lamp-black is obtained by imperfectly burning 
pitch or tar. The dense ' cloud of smoke is conducted 
into a chamber lined with sacking, upon which the 
soot collects. It is largely used in painting. It is 
mixed with clay to form black drawing crayons, and 
with linseed oil to make printers' ink. Lamp-black 
has peculiar properties which fit it for printing. 
Nothing in nature could supply its place. No mat- 
ter how finely it is pulverized, it retains its dead- 
black color. The minutest particle is as black as the 
largest mass. It is insoluble in all liquids. It never 

* The graphite and clay are mixed with water to a semi-solid mass, 
which is then placed in a short iron cylinder having a small opening in the 
bottom and forced through the hole by pressure. In this way a long 
plastic thread is obtained, which is cut into the required lengths and 
heated. 



CARBON. 57 

decays. The paper may molder ; we may even bum 
it, and still, in the ashes, we can trace the form 
of the printed letter. The ancients used an ink 
composed of gum-water and lamp-black, and manu- 
scripts have been exhumed from the ruins of Pompeii 
and Herculaneum which are yet perfectly legible. 

Soot is unburnt carbon which passes off from a 
lamp or fire when there is not enough present to 
combine with all the C of the fuel. This, therefore, 
comes away in flakes, and blackens the chimney of 
the lamp or lodges in the chimney of the house. 
After a time, a large quantity having collected, we 
are startled by the cry, " The chimney is on fire ! " 
while with a great roar and flame the soot burns 
out. This unpleasant occurrence is much more fre- 
quent when green wood is used for fuel. The H 2 
of the wood absorbs much of the heat of the fire, 
and so permits the C to pass off unconsumed. 

Charcoal is made by burning piles of wood, so 
covered over with turf as to prevent free access of 
air. The volatile gases, water, etc., are driven off 
and the C left behind. This forms about f of the 
bulk of the wood and | its weight. Charcoal for 
gunpowder and for medicinal purposes is prepared 
by heating willow or poplar wood in iron retorts. 

Coke is obtained by distilling the water, tar, and 
volatile gases from bituminous coal. It is burned in 
locomotives, blast-furnaces, etc. 

Gas-carbon is formed on the interior of the re- 
torts used in coal-gas works. It has a metallic luster, 
and will scratch glass. 



58 



INORGANIC CHEMISTRY. 
FrG. 23. 




Making charcoal. 

Animal Charcoal, or bone-black, is made by heat- 
ing bones in close vessels. Mixed with H 2 S0 4 , it 
forms the basis of paste-blacking. It is largely used 
by sugar-refiners (p. 217). Common vinegar filtered 
through it becomes the white vinegar of the pickle 
manufacturers. 

Mineral Coal. — This was formed at an early period 
of the world's history, called the Carboniferous Age. 
The earth's surface was then pervaded by a genial 
tropical climate. The air was denser and richer with 
vegetable food than now. The surface itself was a 
swamp, moist and hot, in which simple ferns towered 
into trunks a foot and a half in diameter ; and where 
plants like those which creep at our feet to-day, or 



CARBON. 59 

are known only as rushes or grasses, grew to the 
height of lofty trees. The song of bird or hum of 
insect rarely echoed through the mighty fern-forests ; 
but a strange and grotesque vegetation flourished 
with more than tropical luxuriance. In these swamps 
accumulated a vast deposit of leaves and fallen 
trunks which, under the water, was gradually de- 
composed. In the process of time the earth settled 
at various points and floods poured in, bringing 
sand, pebbles, clay, and mud, filling up all the spaces 
between the trees that were standing and even the 
hollow trunks themselves. The pressure of this soil 
and possibly the internal heat of the earth combined 
to expel the gases from the vegetable deposits and 
convert these into mineral coal.* In time, this section 
was elevated again and another forest flourished, to be 
in its turn converted into coal. Each of these alter- 
nate elevations and depressions produced a layer of 
coal or of soil. In these beds of coal we now find 
the trunks of trees, the outlines of trailing vines, the 
stems and leaves of plants as perfectly preserved as 
in a herbarium, so that the flora of the Carbonifer- 
ous Age is nearly as complete as that of our own. 

Peat is an accumulation of half decomposed veg- 
etable matter in swampy places. \ It is produced 

* Where this process was nearly complete, anthracite coal, and where 
only partially finished, bituminous coal, was formed. The greater the 
pressure, the harder and purer the carbon produced ; unless, however, the 
covering was not sufficiently porous to allow the gases to escape, when 
bituminous coal was the result. 

t These peat-beds are of vast extent. One tenth of Ireland is covered 
by them. A bed near the mouth of .the River Loire, is said to be fifty 
leagues in circumference. 



60 INORGANIC CHEMISTRY. 

mainly by a kind of moss which gradually dies be- 
low as it grows above and thus forms beds of great 
thickness. Sometimes, however, plants may grow 
in the form of a turf and decay, thus collecting a 
vast amount of vegetable debris. This gradually un- 
dergoes a change and becomes a brownish black 
substance, loose and friable in its texture, resembling 
coal, but, unlike it, containing 20 to 30 per cent, 
of 0. Peat is used in large quantities as a fuel. 
For this purpose, it is cut out in square blocks 
and dried in the sun. In some beds it is first finely 
pulverized, then pressed into a very compact form 
like brick. 

Muck is an impure kind of peat, not so fully car- 
bonized ; though the term is frequently applied to 
any black swampy soil which contains a large quan- 
tity of decaying vegetable matter. It is used as a 
fertilizer. 

Various Forms and Uses of Carbon. — We have 
seen in what contrary forms C presents itself. It is 
soft enough for the pencil-sketch and hard enough 
for the glazier's use. Black and opaque, it expresses 
thought on the printed page ; clear and brilliant, it 
gleams and flashes in the diadem of a king. Lamp- 
black and charcoal are readily kindled ; graphite 
resists the heat of the fiercest flame. In the dia- 
mond, carbon is an insulator ; while in the form 
of gas-carbon, it is a conductor of electricity, and 
is used in electrical batteries and in the arc light. 
In our lamps it gives us light ; we burn it in 
our stoves and it gives us heat ; we burn it in 



CARBON. 61 

our engines and it gives us power ; we burn it in 
our bodies and it gives us strength. As fuel, it 
readily unites with 0, yet we spread it as stove- 
polish on our iron-ware to keep the metal from rust- 
ing. It gives firmness to the tree and consistency to 
our flesh. It is the valuable element of all fuel, 
burning oils, and gases. Thus it supplies our wants 
in the most diverse manner, illustrating in every 
phase the forethought of that Being who fitted up 
this world as a home for His children. Infinite Wis- 
dom alone would have stored up such supplies of 
fuel and light and hidden them far under the earth 
away from all danger of accidental combustion, or 
anticipated the requirements alike of luxury and 
the arts. 

Properties of Carbon. — Each of these various sub- 
stances possesses different properties, and yet all 
have certain properties in common which prove 
them to consist of one and the same element. They 
are all tasteless and without color. They are all 
infusible, and all of them, when heated in air or 0, 
unite with the same proportion of 0, forming pre- 
cisely the same compound — carbon dioxide — from 
which the C can be obtained again in the form of 
charcoal. Carbon is the most unchangeable of all 
the elements, so that even in the charcoal we can 
trace all the delicate structure of the plant from 
which it was made. Neither air nor moisture affects 
it. Wheat has been found in the ruins of Hercu- 
laneum that was charred 1800 years ago, and yet 
the kernels are as perfect as if grown last harvest. 



62 INORGANIC CHEMISTRY. 

The ground ends of posts are rendered durable by 
charring. Indeed, some were dug up not long since 
in the bed of the Thames which were placed there 
by the ancient Britons to oppose the passage of 
Julius Caesar and his army. A cubic inch of fine 
charcoal has, it is said, 100 feet of surface, so full 
is it of minute pores. These absorb and condense 
gases to an almost incredible extent. A bit of C 
will take up ninety times its bulk of ammonia. As 
the various gases and the of the air are brought 
so closely together within its pores, rapid oxidation 
is produced, as in the case of spongy platinum (see 
p. 42). Pans of charcoal soon purify the offensive 
air of a hospital. Foul water filtered through C 
loses its impurities. Beer by this process parts not 
only with its color, but with its bitter taste. Ink 
is robbed of its value, and comes out clear and 
transparent as water. 

Deoxidizing or Reducing Action of C. — At a high 
temperature the attraction of C for is powerful. 
In the heat of a furnace it will take it from almost 
the stablest compounds. This fact gives to char- 
coal great value in the arts. Nearly all the metals 
and many of the other elements are locked up in 
the rocks with 0, and C is the key made by the 
Creator for unlocking the treasure-houses of nature 
for the supply of our wants. By noticing the process 
of preparing zinc, iron, phosphorus, etc., we shall 
see the importance of this property of C. A very 
pretty illustration is shown by placing a few grains 
of litharge (PbO) on a flat piece of charcoal, and 



CARBON. 



63 






Fig. 24. 




PbO on charcoal. 



directing upon it the flame of a blow-pipe. The 
metal will immediately appear in 
little sparkling globules. 

Compounds. — Carbon Dioxide, 
C0 2 . — Occurrence. — This gas is com- 
monly known as Carbonic Acid. It 
is found combined with lime in a 
large class of salts, known as the carbonates, viz., 
limestone, marble, chalk, etc., forming nearly one 
half of their weight, and almost one seventh of 
the crust of the earth. It comprises 10 f )00 of the 
atmosphere. It is produced throughout nature in 
immense quantities. Wherever C burns, in . fires, 
lights, decay, volcanoes — in a word, in all those va- 
rious forms of combustion of which we spoke under 
the subject of 0, where that gas unites with C, C0 2 
is the result. Each adult exhales daily about 8| oz. 
of carbon changed to this invisible gas. Each bushel 
of charcoal, in burning, produces not far from 2500 
gallons. A lighted candle gives off about four gal- 
lons per hour. 

Preparation. — For experimental purposes, C0 2 is 
prepared by pouring hydrochloric (muriatic) acid on 
marble or chalk. The reaction may be represented 
as follows : 

CaC0 3 + 2HC1 = CaCl 2 + H 2 + C0 2 . 

The CO 2 is liberated rapidly and, as it is much 
heavier than air, may be collected by downward dis- 
placement (see Fig. 2 5), while the calcium chloride 
remains dissolved in the water of the flask. 



64 



INOEGANIC CHEMISTRY. 



The test for C0 2 is clear lime-water. If we ex- 
pose a saucer of lime-water to the air, the surface 
of the solution will soon be covered with a thin 



Fig. 25. 




Preparing CO a .* 

film of calcium carbonate (carbonate of lime), thus 
showing that there is C0 2 in the atmosphere ; or 
if we breathe by means of a tube through lime- 
water, the solution will become turbid and milky, 
thus proving the presence of C0 2 in our breath ; by 
breathing through the liquid a little longer it will 
become clear, as the carbonate will dissolve in an 
excess of C0 2 .f 

* Twist a wire around the neck of a small, wide-mouthed vial, to serve 
as a bucket. Dip the CO a with it upward from the jar and test with a 
lighted match. Dip the H (Fig. 15) downward, and test in same way. This 
illustrates in a striking manner the difference between the gases in respect 
to specific gravity and combustion. 

t Burn a piece of charcoal or a candle in a jar of 0. Pour in a little 
lime-water and shake it well, when there will be a precipitation of chalk 
(calcium carbonate). Hold a jar of air over a burning lamp or jet of coal- 
gas, or breathe into the jar and apply the test. 



CARBON. 



65 



Properties. — C0 2 is a colorless, odorless, trans- 
parent gas, with a slightly acid taste, and is a non- 
supporter of combustion. Since it is heavier than 
air, many amusing experiments can be performed 



Fig. 26. 




Pouring CO a down an inclined plane. 

with it; It will run down an inclined plane, can 
be poured from one dish to another, drawn off by 
a siphon, dipped up with a bucket like water, or 
weighed in a pair of scales like lead. 

To show the C in C0 2 , hold a strip of Mg foil 
in a flame until well ignited, then insert in a jar 
of the gas. White flakes of magnesium oxide * 
(MgO) mixed with black particles of charcoal will be 
deposited. 

* These may be dissolved by dilute HjST0 3 , and the black C made more 
distinct. 



66 



INORGANIC CHEMISTRY. 
Pig. 27. 




Fig. 28. 



Weighing C0 2 . 

Asphyxia. — C0 2 accumulates in old wells and cel- 
lars, where it has cost the lives of many incautious 
persons.* The test of lowering a lighted candle should 
always be employed. If that be extinguished, your 
life would be in danger of " going out" 
in the same way, should you descend. 
The gas may be dipped out like water, 
or the well may be purified by lowering 
pans of slaked lime or lighted coals 
which, when cool, will absorb the nox- 
ious gas. The coals may be re-ignited, 
and lowered repeatedly until the result 
is reached, f Persons have been suffo- 
cated by burning charcoal in an open 
furnace in a closed room.J .In France, 
suicide is sometimes committed in this manner. The 

* "Three or four per cent, of C0 3 in the air acts aa a narcotic poison 
"by preventing the proper action of the air upon the blood."— Miller. 

t A well in which a candle would not burn within twenty-six feet of 
the bottom, was thus purified in a single afternoon. 

$ The fumes of burning charcoal owe their deadly property largely to 
the presence of CO (page 70), one per cent, of which in the air causes 
headache. 




CO a on a 
light. 



CARBON. 67 

antidote is to bring the sufferer into the fresh air 
and dash cold water upon his face. In the cele- 
brated Grotto del Cane, near Naples, the gas accu- 
mulates upon the floor, so that a man living near 
amuses visitors, for a small fee, by leading his dog 
into the cave. He experiences no ill effects himself, 
but the dog falls senseless. On being drawn into 
the open air, the animal soon revives, and is ready 
to pick up his bit of black bread and enjoy this re- 
ward for his demonstration of the properties of C0 2 . 
C0 2 in Mines. — Miners call C0 2 choke-damp. It is 
produced by the combustion of fire-damp (see p. 71), 
which accumulates in deep mines,* and when mixed 
with air, explodes like gunpowder, forming dense vol- 
umes of CO 2 , which instantly destroys the lives of 
all who may have escaped the flames of the explo- 
sion.! CO 2 has been used for the purpose of extin- 
guishing fires in coal-mines. A mine near Sterling, 
England, had burned for thirty years, consuming a 

* The word gas was first used in the seventeenth century. Explosions, 
strange noises and lurid flames had been seen in mines, caves, etc. The 
alchemists, whose earthen vessels often exploded with terrific violence, 
commenced their experiments with prayer and placed on their crucibles 
the sign of the cross— hence the name crucible from crux (gen. cimcis), a 
cross. All these manifestations were supposed to be the work of invisible 
spirits, to whom the name gdst or geist, a ghost or spirit, was applied. The 
miners were in special danger from these unseen adversaries, and it is said 
that their church service contained the petition, "From spirits, good Lord, 
deliver us!" The names "spirits of wine," "spirits of niter," etc., are a 
relic of the superstitions of that time. 

t Where CO a alone is found, it is not considered as dangerous as the 
fire-damp^ since it will not burn ; and it is said that miners will even venture 
"where the air is so foul that the candles go out, and are then re-lighted 
from the coal on the wick by swinging them quickly through the air, 
when they burn a little while and then go out, and are re-lighted in the 
same way." 



68 INORGANIC CHEMISTRY. 

seam of coal nine feet thick, over an area of twenty- 
six acres. C0 2 , eight million cubic feet of which 
were required, was poured into the mine, in a con- 
tinuous stream, day and night, for three weeks. The 
mine was then cooled with water, and within a 
month from the commencement of the operation, 
was ready for the resumption of work. 

Absorption of C0 2 by Liquids. — Water dissolves 
its own volume of C0 2 under the ordinary pressure 
of the atmosphere, forming a solution of carbonic 
acid; C0 2 + H 2 becoming H 2 C0 3 . With increased 
pressure a much greater amount will be absorbed. 
"Soda water" contains no soda, but is simply H 2 
saturated with C0 2 in a copper receiver strong 
enough to resist the pressure of ten or twelve atmos- 
pheres. The gas gives the H 2 a pleasant, pungent, 
slightly acid taste, and by its escape, w^hen exposed 
to the air, produces a brisk effervescence.* In beer, 
ginger-pop, cider, wine, etc., the C0 2 is produced by 
fermentation, f The gas escapes rapidly through cider 
and wine, and so produces only a sparkling ; while 
in a thick, viscid liquid, like beer, the bubbles are 
partly confined, and hence cause it to foam and 
froth. In canned fruits, catsup, etc., the " souring" of 
the vegetables produces C0 2 , which sometimes drives 
out the cork or bursts the bottles with a loud report. 

* Pass a current of C0 2 through a gill of water. Add a few drops of 
blue litmus-solution. It will immediately redden. Boil the water, when 
the gas will escape and the water become blue. 

t Dissolve an ounce of sugar in ten times its weight of water. Put it 
in a flask and add a little fresh brewer's yeast." If kept warm, in a short 
time it will give off C0 2 , which may be tested. 



CARBON. 69 

Liquid C0 2 . — By a pressure of thirty-six atmos- 
pheres, at a temperature of 32°F., C0 2 becomes a 
colorless liquid very much like H 2 0. When this is 
exposed to the air, it evaporates so rapidly that a 
portion is frozen into a snowy solid which blisters the 
flesh like red-hot iron. By means of solid C0 2 , Hg 
can be readily frozen. When mixed with ether and 
evaporated under the exhausted receiver of an air- 
pump, a cold of — 110°C. may be produced. (See 
" Physics," p. 191.) 

Ventilation. — The relation of C0 2 to life is most 
important, and can not be too often dwelt upon. 
We exhale constantly this dangerous gas, and if fresh 
air is not furnished continuously, we are forced to 
rebreathe that which our lungs have just expelled.* 
The languor and sleepiness we feel in a crowded 
assembly, are the natural effects of the vitiated 
atmosphere.f The idea of drinking in at every 
breath the exhalations that load the air of a crowded, 
promiscuous assembly-room, is a most disgusting 
one. We shun impurity in every form ; we dislike 
to wear the clothes of another, or to eat from the 
same dish ; we shrink from contact with the filthy, 
and yet sitting in the same room inhale their pol- 

* It is a fact, as poetical as it is characteristic, that when the air comes 
forth from the lungs, it is charged with the seeds of disease ; yet, as it 
passes out, it produces all the tones of the human voice, all songs, and 
prayers, and social converse. Thus the gross and deadly is, by a divine 
simplicity, made refined and spiritual, and caused to minister to our highest 
happiness and welfare. 

t It should be noted that the deleterious effects of ill ventilation arise 
not only from the presence of COo, but from the organic particles given off 
in the breath and exhaled from the skin. (See "Physiology," p. 93,) Be- 
breathed air is a fruitful source of consumption and scrofula. 



70 



INORGANIC CHEMISTRY. 
Pig. 29. 




Testing the currents of air to and from flame. 

luted breath. Health and cleanliness alike require 
that we should carefully ventilate public buildings, 
school-rooms and sleeping apartments.* 

Carbon Monoxide, CO, is a colorless, almost odor- 
less gas nearly insoluble in water. It burns with a 

* Two openings are necessary to ventilate a room. To illustrate this, 
set a lighted candle in a plate of water, as shown in Mg. 29. Cover it with 
an open jar, over the neck of which is placed a common lamp-chimney. 
The light will soon be extinguished on account of the consumption of O, 
and the formation of C0 2 . Raise the jar at one side a trifle above the 
water, and the candle, if re-lighted, will burn steadily— fresh air coming in 
below, and the refuse passing off at the top. Replace the jar, and as the 
candle is flickering, insert in the chimney a slip of card, thus dividing the 
passage, when the light will brighten again. Hold a bit of smoldering 
touch-paper (page 32) at the top, and the smoke will show two opposite 
currents of air established in the chimney. Mines have been ventilated in 
this way by dividing the shaft. More commonly, however, they have two 
shafts at a little distance apart. 



CARBON. 



71 



pale blue flame, absorbing an atom of from the 
air and becoming C0 2 . It is seen burning thus 
in our coal-stoves and at the tops of tall furnace- 
chimneys. It is often formed abundantly through 
the action of heated carbon on C0 2 . When air 
enters at the bottom of a clear fire, C0 2 is formed 
at once ; but this gas passing through the hot em- 
bers takes up a further quantity of C, becoming 
changed into CO:* C + C0 2 = 2 CO, the volume of 
the gas being exactly doubled in bulk thereby. CO 
is a deadly poison, and escaping from coal-fires in a 
close room, has often prodi^ced death. Both CO and 
C0 2 leak through the pores of cast Fe when heated, 
and still further injure the air of our houses and 
necessitate ventilation. The offensive odor which 
comes out on opening the 
door of our coal-stoves 
is caused by the com- 
pounds of S mixed with 
the CO. 

Marsh-Gas. — Light Car- 
buretted Hydrogen, CH 4 . 
— This we have already 
spoken of under C0 2 , as 
the dreaded fire-damp of 

miners. It is colorless, tasteless, odorless, and burns 
with a pale yellowish flame. It is formed in swamps 
and low marshy places by the decomposition of 



Fig. 30. 




Collecting Marsh-gas. 



* This fact is of great importance, since thereby much heat is wasted. 
Stoves are often so constructed as to admit fresh air just above the grate, 
thus consuming this gas. 



72 INORGANIC CHEMISTRY. 

vegetable matter, and on stirring the mud beneath, 
will be seen bubbling up through the water. It may 
be collected in the manner shown in Fig. 30. It 
rises from the earth in great quantities at many 
places. At Fredonia, N. Y., it is used in lighting the 
village. At Kanawha, Va., it was, until lately, em- 
ployed as fuel for evaporating the brine in the 
manufacture of salt. In the oil-wells of Pennsyl- 
vania, it frequently bursts forth with explosive vio- 
lence, throwing the oil high into the air. 

defiant Gas. — Heavy Carburetted Hydrogen, C 2 H 4 . 
— This is a colorless gas, with a sweet, pleasant odor, 
and burns with a clear white lights It may be 
easily prepared by heating in a large retort a mixt- 
ure of one part of alcohol with six of H 2 S0 4 . 

Coal-Gas is a variable mixture of combustible 
gases and vapors, which may be divided into two 
classes : 1st. The illuminating constituents, oleflant 
gas being the most important ; and 2d. The diluents, 
chiefly H, CO, and CH 4 . Olefiant gas and hydrocar- 
bons having a similar composition, give whiteness to 
the flame; while the H, CH 4 , and CO have little 
illuminating power. Bituminous coal is heated in 
large iron retorts, B, until the volatile constituents are 
driven 'off and only coke is left. Among the former 
are coal-tar, NH 3 , C0 2 , CO, N, compounds of S, CH 4 , 
and C 2 H 4 .f This mixture is led through the curved 

* A very characteristic property of oleflant gas is its power of uniting 
directly with, an equal volume of CI to form a heavy oily liquid called 
Dutch liquid. It is to this that it owes its name of olefiant gas. 

t None of these substances exist in coal. They are formed by the 
action of heat, which causes the H, C, O, N, and S to combine and make 
a multiplicity of compounds. 



CARBON. 



73 



pipes, d, beneath the H 2 
in the hydraulic main, 
F) along the tube, g, to 
the tar cistern ; thence 
up and down the con- 
denser, j. On the way it 
becomes cooled and loses 
its coal-tar, ammoniacal 
salts,* and liquid hydro- 
carbons. Lastly, it is 
passed over lime, L m, 
which absorbs the C0 2 
and the H 2 S.f The re- 
maining gases form the 
mixture we call "gas." 
This is collected in the 
gasometer, P, the weight 
of which forces it through 
all the little gas-pipes, 
and up to every jet in 
the city. 

Coal-gas is very poison- 

* The XH 3 is neutralized by HC1, 
thus forming chloride of ammonium 
(sal-ammoniac, NH 4 C1). On evapo- 
ration and sublimation, the tough, 
fibrous crystals of the salt are ob- 
tained. 

t The removal of the sulphur 
compounds is especially important, 
since, when burned, they furnish 
sulphurous and sulphuric acids. 
These acids would cause very great 
injury to books, paintings, and fur- 
niture. 



Fig. 31. 




Manufacture of Coal-gas. 



74 INORGANIC CHEMISTRY. 

ous, and even in small quantities exceedingly delete- 
rious. When mixed with air, it explodes with great 
violence. Its unpleasant odor, though often annoy- 
ing, is a great protection, as we are thereby warned 
of its presence. 

Water-Gas. — This gas, which is now extensively 
used both for heating and illuminating purposes, is 
made by leading steam over red-hot coke. The steam 
(H 2 0) is decomposed by the C of the coal with the 
production of H and CO, as shown in the following 

equation : 

C + H 2 = CO + 2H. 

Both H and CO are gases, and burn with great heat ; 
when passed through petroleum oils, they become 
" carburetted " and burn with a luminous flame. 

Cyanogen,* Cy = CN. — Preparation. — As N and C 
do not combine directly, this gas is obtained in an 
indirect way. Mix the parings of horns, hides, etc., 
with pearlash (potassium carbonate) and iron filings, 
and heat in a close vessel. The N and C of the 
animal substances, in their nascent state, will com- 
bine, forming Cy ; this, uniting with the Fe and K, 
will produce potassium ferro-cyanide (yellow prussiate 
of potash), a solution of which yields fine yellow 
crystals. From this salt mercury cyanide is made, 
which, when heated, decomposes into Hg and Cy. 

Properties. — Cy is a transparent, colorless gas, with 
a penetrating odor. It burns with a characteristic 
rose-edged purple flame and is exceedingly poisonous. 

* The term cyanogen means " blue producer " ; this gas being the char- 
acteristic constituent of Prussian blue. 



COMBUSTION. 75 

It is very interesting from the fact that, though a 
compound, it unites directly witih the metals like 
the elements CI, Br, etc. It is therefore called a 
compound radical (root). AYe shall find this subject 
of great importance in Organic Chemistry. 

Hydrocyanic Acid, HCy. — Prussic acid, as it is com- 
monly called, is a fearful poison. A single drop on 
the tongue of a large dog is said to produce instant 
death. NH 3 , cautiously inhaled, is its antidote. Its 
bitter flavor is detected in peach blossoms, the ker- 
nels of plums or peaches, bitter almonds, and the 
leaves of wild cherry. 

Fulminic Acid (fulmen, a thunder-bolt). — This com- 
pound of Cy is known only as combined with the 
various metals forming fulminates, which are remark- 
ably explosive. Fulminating mercury was used to fill 
the bombs with which the life of Xapoleon III. was 
attempted in 1858. It is employed in making gun- 
caps. A drop of gum is first put in the bottom of the 
cap, over which is sprinkled a mixture of saltpeter, sul- 
phur, and fulminating mercury, and this is sometimes 
covered with varnish to protect it from any moisture. 



COMBUSTION. 

Combustion, in general, is the rapid union of a 
substance with 0, and is accompanied by heat and 
light.* 

Chemistry of a Fire. — Our fuel and lights, such 

* There are forms of combustion known to the chemist which are not 
oxidation; as the union of S and Cu. (See page 87, note.) 



76 INORGANIC CHEMISTRY. 

as wood, coal, oil, tallow, etc., consist mainly of C 
and H, and are, therefore, called hydrocarbons. In 
burning they unite with the of the air, forming 
H 2 and C0 2 . These both pass off, the one as a 
vapor, the other as a gas. In a long stove-pipe, the 
H 2 is sometimes condensed, and drips down, bringing 
soot upon our carpets. Ashes comprise the mineral 
matter contained in the fuel, united with some of 
the CO 2 produced in the fire. When we first put 
fuel on a fire, the H is liberated in combination with 
some C, in the form of marsh, or olefiant gas. This 
burns with a flame. Then, the volatile gases having 
passed off, we have left the C, which burns without 
flame. In maple there is much more C than in pine, 
so it forms a good "bed of coals." In the burning 
of fuel there is no annihilation; but the H 2 0, C0 2 , 
and the ashes, weigh as much as the wood and the 
that combined with it. No matter how rapidly 
the fire burns, even in the blaze of the fiercest 
conflagration, the elements unite in exact atomic 
proportions. 

C is most admirably fitted for fuel, since the 
product of its combustion is a gas. Were it a solid, 
our fires would be choked, and before each supply 
of fresh fuel we should be compelled to remove the 
ashes, which would be more bulky than the original 
fuel. In the case of a candle or lamp it would be 
still more annoying, as the solid product would fall 
around our rooms. Still another useful property is 
the infusibility of C. Did C melt like Zn or Pb on the 
application of heat, how quickly in a hot fire would 



COMBUSTION. 



77 



Fig 32. 



the coal and wood run down through the grate and 
out upon the floor in a liquid mass ! 

Chemistry of a Candle. — Flame is burn- 
ing gas. A candle is a small " gas-work," 
and its flame is the same as that of a " gas- 
burner." First, we have a little cupful of 
tallow melted by the heat of the fire above. 
The ascending currents of cool air which 
supply the light with also keep the sides 
of the cup hard, unless the wind blows 
the flame downward, when the banks break, 
there is a crevasse, and our "candle runs 
down." Next, the melted tallow is carried 
by capillary attraction up the small tubes 

of the wick into the flame. 

is turned into gas by the heat, 




Form of 
flame. 



Fig. 33. 



There it 
Flame 
is always hollow, and at the center, 
near the wick, is the gas just formed. 
If a match be placed across a light, it 
will burn off at each side, in the ring 
of the flame, while the center will be 
unblackened.* The gas may be con- 
ducted out of the flame by a small 
pipe, and burned at a little distance 
from the candle. Flame is hollow be- 
cause there is no at the center. As 
Match in flame; me the gases pass upward and outward 

S and P being un- _ . .. . , . , , 

consumed. from the wick, they come in contact 




* Take a sheet of white paper and thrust it quickly down upon the 
flame of a candle or lamp. It will burn in a ring, and when the paper is 
removed the center will be found unblackened. 



78 



INORGANIC CHEMISTRY. 



with the of the air, and the H, requiring least heat 
to unite, burns first, forming H 2 0. The carbon which 
was united with the H is now set tree in tiny par- 
ticles, which floating around in the flame of the 
burning H become white-hot.* They each send out 
a delicate wave of light, and passing on to the outer 
part where there is more 0, burn, forming C0 2 . 



Fig. 34. 




Testing the CO a of a flame by drawing the gas through lime-water. 

The flame is blue at the bottom, because there is so 
much at that point that the H and burn to- 
gether, and so give little light. 

The H 2 may be condensed on any cold surface. 
The CO 2 may be tested by passing the invisible 
vapor of a candle through lime-water. \ The wick of 



* Frankland has shown that the intensity of a flame, in general, is 
determined by the density of the gas : thus, a jet of H burning under a 
pressure of ten atmospheres will furnish sufficient light to read a news- 
paper at a distance of two feet. 

t See also pages 63 and 64. 



COMBUSTION. 79 

a candle does not burn, because of the lack of at 
the center. It, however, is charred, as all the vola- 
tile gas is driven off by the heat. If a portion falls 
over to the outer part where there is 0, it burns as 
a coal. If we blow out a candle quickly, the gas 
still passes off and we can relight it with an ignited 
match held at some distance from the wick. The 
tapering form of the flame is due to the currents of 
air that sweep up from all sides toward it. The 
candle must be snuffed, because the long wick would 
cool the blaze below the igniting point of C and 0, 
and the C would pass off unconsumed as smoke. A 
draught of air, or any cold substance thrust into 
the flame, produces the same result and deposits the 
C as soot. Plaited wicks are 
sometimes used, which, being 
thin, fall over to the outside 
and burn, requiring no snuffing. 
Chemistry of a Lamp. — A 
chimney confines the hot air, 
and makes a draught of air to 
feed the flame. A flat wick is 
used, as it presents more sur- 

„ . H 2 condensed from a Jta?ne. 

tace to the action of the 0. 

Argand lamps have a hollow wick which admits air 
into the center of the blaze, and thus gives a larger 
luminous surface. The film which gathers on a chim- 
ney when we first light a lamp, is the H 2 produced 
in the flame condensed on the cold glass. Spirits 
of turpentine, tar, pine-wood, etc., contain an excess 
of C, and not enough H to heat it to the igniting 




80 



INORGANIC CHEMISTRY. 



Fig. 36. 



point. These, therefore, produce clouds of soot. Alco- 
hol contains an excess of H and less C, hence it 
gives off great heat and little light. 
Davy's Safety Lamp, used by 
miners, consists of an ordinary oil- 
lamp surrounded by a cylinder of 
fine wire gauze. When it is carried 
into an atmosphere containing the 
dreaded fire-damp, the flame en- 
larges and becomes pale, and when 
the quantity increases, the gas will 
quietly burn on the inside of the 
cylinder.* There is no danger of an 
explosion so long as the gauze re- 
mains perfect and draughts are 
avoided, f Through 
carelessness, how- 
ever, fearful acci- 
dents have oc- 
curred. Miners be- 
come extremely negligent, and an 
account is given of an explosion, in 
which about a hundred persons were 
killed, caused by a lamp being hung 
on a nail by a hole broken through the wire gauze. 




Fig. 37. 



Davy^s Safety Lamp, 




Flame lighted over 
wire gauze. 



* The principle of the lamp can be illustrated by holding a nne wire 
gauze over the flame of a candle or gas-burner (Fig. 37). The flame will not 
pass through, since the wire will conduct away the heat and so reduce the 
temperature below the igniting point. A jet of gas, issuing at a low tem- 
perature, may be lighted on either side of the gauze at pleasure. 

f At such a time, however, the wise miner will leave the place of 
danger, lest the metal should melt and the fire escape to the gas, when an 
explosion would ensue. 



COMBUSTION. 



81 



Fig. 38. 



The Bunsen Burner, which is used in the labo- 
ratory, consists of a gas-jet, a, surrounded by a fnetal 
tube, c, at the bottom of which are openings, 5, for 
the admission of air. 
The gas passes up the 
tube, mingles with 
the air which it draws 
in through the open- 
ings, and burns at the 
top without smoke. 
The is supplied in 
sufficient quantity to 
burn the H and C si- 
multaneously ; hence 
there is great heat 
with little light, and 
no soot is deposited 
on the bottom of 
dishes heated by this 
burner. 

The Oxy-hydrogen Blow-pipe is so constructed 
that a jet of is introduced into the center of one 
of burning H, thus producing a solid flame. A watch- 
spring will burn in it with a shower of sparks. Pt, 
the most infusible of metals, will readily melt. In the 
common flame, as we have seen, the little particles 
of solid C, heated by the burning H, produce the 
light. As there is no solid body in the blow-pipe 
flame, it is scarcely luminous. If, however, we insert 
in it a bit of CaO, or MgO, a dazzling light is pro- 
duced. This is called the " Drummond," '" Lime," or 




The Bunsen Burner. 



82 



IK ORGANIC CHEMISTRY. 
Fig. 39. 




The Oxy-hydrogen Blow-pipe. 

"Calcium" Light, and with a properly arranged re- 
flector has been seen at a distance of one hundred 
and eight miles. 



COMBUSTION. 



83 



Fig. 40. 






a 
7 



Mouth Blow-pipe. — In the common blow-pipe, used 

by jewelers and mineralogists, a current of air from 

the mouth* is thrown across the 

light just above the wick. The flame 

loses its brilliancy and is driven one 

side in the form of a cone (Fig. 41). 

Its size, also, is less, and since the 

combustion is concentrated into a 

smaller space, its temperature is 

higher than that of an ordinary 

flame. The hottest point is at 5, a 

little beyond the tip of the inner 

blue cone, because at this place the 

combustion is most complete. The 

inner cone contains CO in excess, 

hot and ready to combine with 

from any substance exposed to it, 

and is therefore called the reducing 

flame. The outer envelope contains 

the in excess, borne 
forward by the jet of 
flame, highly heated 
by it, and ready to 
unite with a metallic 
body. It is therefore 
called the oxidizing 
flame. — Example : Hold 
a copper cent in the 

"reducing flame''; its rust, copper oxide, will be 




CIA 

Common Blow -pipes. 



Eig. 41. 



T C 




* The air must come from the mouth by the action of the muscles of 
the cheeks, not from the lungs. 



84 INORGANIC CHEMISTRY. 

cleaned off, and the metal will shine as brightly as, 
if just from the mint. In the " oxidizing flame" a 
film of copper oxide will be formed over the sur- 
face, and as we move the cent the most beautiful 
play of colors will flash from side to side.* 



PRACTICAL QUESTIONS. 

1. Why will pine-wood ignite more easily than maple? 

2. Why is fire-damp more dangerous than choke-damp? 

3. Represent the reaction in making C0 2 , showing the atomic weights, 
as in the preparation of O on page 12. 

4. Should one take a light into a room where the gas is escaping? 

5. Why does it dull a knife to sharpen a pencil? 

6. Where was the C, now contained in the coal, before the Carbon- 
iferous age? 

7. Must the air have then contained more plant food? (p. 58.) 

8. What is the principle of the aquarium? 

9. What test should be employed before going down into an old well 
or cellar? 

10. What causes the sparkle of wine, and the foam of beer? 

11. What causes the cork to fly out of a catsup bottle ? 

12. What physical principle does the solidification of C0 2 illustrate? 

13. Why does the division in the chimney shown in Pig. 29 produce 
opposite currents? 

14. What causes the unpleasant odor of coal-gas? Is it useful? 

15. What causes the sparkling often seen in a gas-light? 

16. Why does H in burning give out more heat than C? 

17. Why do not stones burn as well as wood? 

18. Why does not hemlock make " a good bed of coals " ? 

19. What adaptation of chemical affinities is shown in a light? 

20. Why does snuffing a candle brighten the flame ? 

21. Why is the flame of a candle red or yellow, and that of a kerosene 
oil lamp white? 

* Introduce a small piece of common flint-glass tube into the reducing 
flame. The glass will become opaque and black, because the Pb will be 
reduced from the transparent form of silicate to the opaque condition of 
metal. When this has happened, place the black portion just in front of 
the oxidizing flame. The discoloration will slowly disappear, and the Pb 
will recombine with O from the air and the glass again become transparent. 



THE ATMOSPHERE. 85 

22. Why does a street gas-light burn blue on a windy night? Is the 
light then as intense ? The heat ? 

23. Why does not the lime burn in a calcium-light? 

24. Why is a candle-flame tapering? 

25. Why does a draught of air cause a light to smoke? 

26. What makes the coal at the end of a candle-wick? 

27. Which is the hottest part of a flame? 

28. Why does not a candle-wick burn ? 

29. How does a chimney enable us to burn without smoke highly car- 
boniferous substances like oil? 

30. How much CO Q in 200 lbs. of chalk? 

31. What weight of CO, in a ton of marble? 

32. Why does not a cold saucer held over an alcohol flame blacken, as 
it does over a candle or gas-light? 

33. How much CO a is formed in the combustion of one ton of C ? 

34. What weight of C is there in a ton of CO.,? 

35. How much O is consumed in burning a ton of C? 

36. What weight of sodium carbonate QSTa 2 C0 3 , "carbonate of soda") 
would be required to evolve 12 grams of C0 2 ? 

37. How much CO* will be formed in the combustion of 30 grams 
of CO? 

38. What weight of CaC0 3 would be required to evolve 12 grams of C0 2 ? 

39. What would be the volume of these 12 grams of CO, at 12° C. and 
744 mm A 

40. How much C would be necessary to furnish C0 2 enough to fill a 
gas-holder 10 meters high and 4 meters in diameter when the temperature 
is 25° C. and the barometer stands at 754 ?/?/??.? 

41. Write in double columns the different properties of carbon dioxide 
and carbon monoxide; thus, 

CO, is CO is 

1, non-inflammable. 1, inflammable. 



THE ATMOSPHERE. 

The "air we breathe" consists chiefly of N and 
0, mixed in the proportion of 79 parts of N to 21 
of by volume, or 77 of N to 23 of by weight. 
Besides the N and 0, air always contains C0 2 and 
watery vapor, the former amounting in volume to 4 
parts in 10,000, and the latter varying in amount. 
Another gas, argon, occurs in small quantities. 



86 INORGANIC CHEMISTRY. 

A very clear idea of the proportion of these several 
constituents may be formed by conceiving the air, 
not as now dense near the surface of the earth, and 
gradually becoming rarefied as we ascend,* but of a 
density throughout equal to that which it now pos- 
sesses near the earth. The atmosphere would then 
be about five miles high. The vapor would form 
upon the ground a sheet of H 2 five inches deep, 
next to this the C0 2 a layer of 13 feet, then the 
a layer of one mile, and last of all the N one of four 
miles. f — Graham. In this arrangement we have sup- 
posed the gases to be placed in the order of their 
specific gravity. The atmosphere is not thus com- 
posed in fact, the various gases being equally min- 
gled throughout, in accordance with a principle called 
the "Laiv of the diffusion of Gases." If we throw a 
piece of lead into a brook, it will settle instantly to 
the bottom by the law of gravitation and will remain 
there by the law of inertia. But if we throw into 
the atmosphere a quantity of C0 2 , it will sink for 
an instant, then immediately begin to mingle with 
the surrounding air and soon become dissipated. — 
Example : If we invert an open-mouthed bottle full 
of H over another full of C0 2 , the H, light as it is, 
will sink down into the lower jar; and the C0 2 , 
heavy as it is, will rise into the upper jar ; and in a 
few hours the gases will be found equally mixed. 

* At a height of about 38 miles the air is only T £o as dense as at the 
surface of the earth. At a height of 50 miles it is so extremely rare that 
this is usually given as the height of the atmosphere. 

t The 1ST and O form so large a part, that they are considered in ordi- 
dinary calculation to compose the whole atmosphere. 



THE ATMOSPHERE. 



87 



Fig. 42. 



r 



jiK 



By this law the proportion of the elements of the 
atmosphere is the same every-where, and has not 
varied within historic times. Samples have been 
analyzed from every conceivable place, from 
polar and torrid regions, from prairies and 
mountain -tops, from balloons and mines, 
from crowded capitals and lonesome forests, 
and even from bottles found sealed up in 
the ruins of Herculaneum, and the result is 
almost exactly the same. These gases do 
not form a chemical compound, but a mere 
mechanical mixture,* and they are as dis- 
tinct in the air as so many grains of wheat 
and corn mingled in a measure. 

Each of the constituents of the air has 
its separate use and mission. The action of 
and N we have already seen. 

Uses of C0 2 . Carbonic acid, so deadly to 
animal life, is necessary to the maintenance of the 
vegetable kingdom.. The leaf through its million of 
little stomata, or mouths, drinks in the C0 2 . In that 
minute leaf-laboratory, by the action of the sunbeam, 

* " To illustrate the difference between a mechanical mixture and a 
chemical compound, mix powdered S and filings of Cu. The color of the S 
as well as that of the Cu will disappear, and to the unaided eye will pre- 
sent a uniform greenish tint; with the microscope, however, the particles 
of Cu may be seen lying by the side of those of S ; and we can wash away 
the lighter S with H 2 0, leaving the heavier Cu behind. Here no chemical 
action has occurred ; the S and Cu were only mechanically mixed. If we next 
gently heat some of the mixture it soon begins to glow, and on examining 
the mass we find that both the Cu and the S have disappeared as such, 
that they can not be distinguished even with the most powerful micro- 
scope, and that in their place we have formed a black substance possessing 
properties entirely different from those possessed either by the Cu or 
the S."— Roscoe. 



Diffu- 
sion of 



88 INORGANIC CHEMISTRY. 

the C0 2 is decomposed,* the C being applied to build 
up the plant, and the returned to the air for our use. 
Plants give out as we breathe out C0 2 . We 
furnish vegetables with air for their use, and they in 
turn supply us. There is thus a mutual dependence 
between the animal and the vegetable world. Each 
relies upon the other. Deprived of plants, we should 
soon exhaust the from the air, supply its place with 
C0 2 , and die ; while they, removed from us, would 
soon exhaust the C0 2 , and die as certainly. We pol- 
lute the air while they purify it. Each tiny leaf 
and spire of grass is thus imbibing our foul breath, 
and returning it to us pure and fresh, f This inter- 

* "In order to decompose carbonic acid in our laboratories, we are 
obliged to resort to powerful chemical agents, and to conduct the process 
in vessels composed of resisting materials, under all the violent manifesta- 
tions of light and heat, and we then succeed in liberating the carbon only 
by shutting up the oxygen in a still stronger prison ; but under the quiet 
influences of the sunbeam, and in that most delicate of all structures, a 
vegetable cell, the chains which unite together the two elements fall off, 
and, while the solid carbon is retained to build up the organic structure, 
the oxygen is allowed to return to its home in the atmosphere. There is 
not in the whole range of chemistry a process more wonderful than this. 
We return to it again and again, with ever increasing wonder and admira- 
tion, amazed at the apparent inefficiency of the means, and the stupendous 
magnitude of the result. When standing before a grand conflagration, wit- 
nessing the display of mighty energies there in action, and seeing the 
elements rushing into combination with a force which no human agency 
can withstand, does it seem as if any power could undo that work of 
destruction, and rebuild those beams and rafters which are disappearing 
in the flames? Yet in a few years they will be rebuilt. This mighty force 
will be overcome ; not, however, as we might expect, amidst the convul- 
sion of nature, or the clashing of the elements, but silently, in a delicate 
leaf waving in the sunshine. ,1 — Cooke. 

t Prom this statement it is evident that the foliage of house-plants 
must be healthful. Moreover, there is some reason to believe that the O 
which they exhale is highly ozonized, and therefore of great value in 
destroying miasmic germs. We should remember, however, that flowers 
exhale CO a , and the odor of certain plants, and the pollen of others, are 



THE ATMOSPHERE. 
Fia. 43. 



89 




Apparatus arranged to catch the O evolved from a sprig of 



change of office is so exactly balanced, that, as we 
have seen, the variation in the proportion of C0 2 and 
of 0, in the open air, is almost imperceptible.* 

very injurious. Plants and flowers, which to one person are inocuous, are 
to another detrimental. Thus the fragrance of new-mown grass, which is 
so agreeable to some, produces in others what is termed the hay-fever ; due, 
it is said, to the pollen of the grass. Each family, therefore, must deter- 
mine for itself what should be excluded from its collection. It is evident 
that flowerless plants, like the ivy, etc., are harmless, while the cheerful- 
ness given to an apartment by even a few pots of flowers on a window- 
bench, should induce one to take some trouble in order to make a selection 
which will not only beautify but purify the room. 

* "Two hundred million tons of coal are now annually burned, pro- 
ducing six hundred million tons of CO Q . A century ago, hardly a fraction 
of that amount was burned, yet this enormous aggregate has not changed 
the proportion in the least."— Youmans. 



90 INOEGAJSTIC CHEMISTRY. 

Plants Store up Solar Energy. — The sunbeam, 
which is thus strong enough to wrench apart the C 
and 0, sends out the full of potential energy and 
builds up the plant. The energy of the sunbeam is 
transformed into the potential energy of and of the 
vegetable structure. The sun shining on a meadow 
causes the grass to grow. In this process energy of 
the sun is absorbed, which is again rendered available 
as active energy by the animal which feeds upon the 
grass. A tree towers upward through a century of sun- 
shine. When burned, it sets free as much energy as 
was needed to perfect its growth. A bushel of corn, 
then, represents not alone so much C, H, and 0, but also 
an amount of sun-energy which is available for any 
purpose to which we wish to apply it. (See Con- 
clusion,) 

Animals Spend Solar Energy. — In the process of 
digestion the energy stored in . the plant is trans- 
ferred to the animal, is given out by its muscles on 
their oxidation and produces motion, heat, etc. NH 3 , 
CO 2 , and H 2 are decomposed by the plant and 
organized into complex molecules (see p. 185), full 
of potential energy. The animal oxidizes the organic 
molecules, and breaks them up into NH 3 , C0 2 , and 
H 2 again — simple molecules robbed of energy which 
the animal has used. Thus the plant builds up and 
the animal tears down. The plant garners in the 
sunbeam and the animal scatters it again. The 
plant reduces and the animal oxidizes. 

Uses of Watery Vapor. — We have already seen 
the uses of H 2 0. As vapor, it is every-where present 



THE ATMOSPHERE. 91 

and ready to supply the wants of animals and plants. 
Were the air perfectly dry, our flesh would become 
shriveled like a mummy's, and leaves would wither 
as in an African simoom. Rivers and streams flow 
to the ocean ; yet all their fountains are fed by the 
currents that move in the air above us. H 2 rises 
as vapor, flows on to colder regions, falls as rain, 
sleet, snow, or hail, and then wends its way back to 
the ocean, turning many a water-wheel on its way 
as it parts with its potential energy. 

Permanence of the Atmosphere. — The elements 
of the air unite to form HN0 3 only by the passage 
of electricity, and then in minute quantities. If they 
combined more readily we should be constantly ex- 
posed to a shower of this corrosive acid that would 
be destructive to all vegetation, clothing, and even 
our bodies themselves. — 0, N, and C0 2 are converted 
into liquids only by an apparatus specially made 
for the purpose, and under circumstances which 
could rarely, if ever, occur in Nature.* These sub- 
stances are therefore constantly in the condition 
promptly to supply the demands of animals and 
plants. — Watery vapor, on the contrary, is deposited 
as dew or rain by even slight changes of tem- 
perature ; this readiness of condensation is equally 
necessary to meet the wants of animal and vege- 
table life. 



* The liquefaction of the so-called "permanent gases," ET, O, H, etc., 
was first accomplished in 1877 by Cailletet of Paris and Pictet of G-eneva, 
almost simultaneously. 



92 INORGANIC CHEMISTRY. 



THE HA LOGENS. 



Chlorine. . Symbol, CI 

Iodine " I 

Bromine.. u Br 
Fluorine.. (( F 



Atomic Weight 35,5; Specific Gravity, 2,45, 

127.; " 4,95, 

(( " 80.; " 3,19, 
" " 19, 



These four elements are closely allied, and are 
known as the halogens, from hals, salt, because they 
form a class of compounds (Haloids) which resemble 
common salt (NaCl).* 

Chlorine is named from its green color. It is 
chiefly found in salt, of which it forms 60 per cent. 
It may be prepared by gently heating a mixture 
Mn0 2 and hydrochloric acid: 

Mn0 2 + 4HC1 = MnCI 2 + 2H 2 + 2C1 ; 

or still more conveniently from NaCl, Mn0 2 , and H 2 S0 4 . 
On slightly warming this mixture a regular and 
copious evolution of CI takes place. CI is heavier 
than common air, and hence may be collected by 
displacement, as in the preparation of C0 2 . 

Properties. — CI has a greenish-yellow color, and a 
peculiarly disagreeable odor. It produces a suffo- 

* In comparing the halogens with one another, the chemical activity of 
E, which has the smallest atomic weight, is the most powerful ; next in 
the order of activity is CI, then Br, and, lastly, I, the atomic weight 
increasing as the chemical energy declines. CI is gaseous, Br, liquid, and 
I solid. The specific gravity, the fusing point, and the boiling point, 
rise as the atomic weight increases. The halogens combine energetically 
with the metals, and, when united with the same metal, furnish com- 
pounds which are isomorphous ; that is to say, they all crystallize in the 
same form— potassium fluoride, chloride, bromide, and iodide, for example, 
all crystallize in cubes. Each, also, forms with H a soluble, powerful acid 
— HC1, HI, HBr, HE. 



THE HALOGENS. 
Fig. 44. 



93 




Preparing CI. 

eating cough, which can be relieved by breathing 
ammonia or ether. It is incombustible. If a lighted 
candle is lowered into a jar of CI, it burns with a 
red smoky flame for a short time, and then goes 
out. Arsenic, Dutch gold-leaf, phosphorus, etc., com- 
bine with it so rapidly as to inflame. Powdered 
antimony slowly dropped into it produces a shower 
of brilliant sparks. Cold water absorbs about twice 
its volume of the gas. 

CI has a very strong affinity for H. When H and 
CI are mixed in the dark and exposed to direct sun- 
light, they unite with an explosion ; and CI is able 
to take H away from its combination with other 
substances. Thus it acts energetically on turpen- 
tine (C, H I6 ), uniting with its H and setting its C 



94 



INORGANIC CHEMISTRY. 



free in a great cloud of soot. Another example is 

seen in the way in which 



Fig. 45. 



Fig. 46. 




Candle in CI. 



Turpentine in CI. 



a candle burns in the 
gas. It will even decom- 
pose water to get H, set- 
ting free in the process. 
This action, like the di- 
rect union of H and CI, 
does not take place in 
the dark ; but if chlorine 
water is exposed to direct 
sunlight, it goes on slowly 
and the can be col- 
lected and tested. The reaction is represented by the 

equation : 

H 2 + 2C1 = 2HC1 + 0. 

This same reaction also takes place without the 
aid of sunlight when there is some substance present 
on which the can readily act. Such substances 
are organic coloring matters, and hence CI can de- 
stroy many dye-stuffs and thus bleach cloth, etc., in 
the presence of moisture. Upon some dyes it probably 
acts directly, converting them into colorless sub- 
stances, but in many cases the color is discharged 
only when moisture is present. In such cases the 
bleaching is a burning or oxidation, and hence CI is 
called an "indirect oxidizing agent." The necessity 
for the presence of moisture is shown by placing two 
strips of colored calico or of litmus paper, one dry 
the other moistened, in different jars of dry CI. The 
is set free by the CI in the nascent state, and 



THE HALOGENS. 95 

hence produces an effect of which the atmospheric 
is incapable. CI discharges the color of indigo, 
writing-ink, wine, etc., almost instantaneously, but 
has no effect on printer's ink, the basis of which is 
C, nor on mineral colors in general. 

Uses. — Bleaching. — In domestic bleaching the 
cloth is first boiled with strong soap, to dissolve the 
grease and wax, and then laid upon the grass, being 
frequently wet to hasten the action of the air and 
sun.* It seems likely that ozone is formed by the 
evaporation of the moisture, and that the bleach- 
ing is really an oxidation by its means. CI is now 
extensively used for bleaching cloth, paper-pulp, 
etc.f It is usually employed in the form of so-called 
u chloride of lime" or bleaching powder. 

Disinfectant. — CI is a powerful disinfectant. It 
breaks up the offensive substance by uniting with 
its H as in bleaching. Other disinfectants, as burnt 
paper, sugar, etc., only disguise the ill odor by sub- 
stituting a stronger one. In the sick-room CI is set 

* This was essentially the process long pursued in Holland, where linens 
were formerly carried for bleaching; hence the term "Holland linen," 
still in use. The H 2 about Haarlem was thought to have peculiar proper- 
ties, and no other could compete with it. Cloths sent there were kept the 
entire summer, and were returned in the fall. Later a similar plan was 
adopted in England. But the vast extent of grass-land required, the time 
occupied, and the temptation to theft, made the process extremely tedious 
and expensive. The statute laws of that time abound in penalties for 
cloth stealing. It is estimated that all the men, women, and children 
in the world could not, by the old way, bleach all the cloth that is now 
used. 

t Stains can be removed from unwlor-ed cloth by " Labarraque's Solution,' ■ 
a compound of CI, which can be obtained of any druggist. Place the cloth 
in this liquid, and if the stain is obstinate, pour on a little boiling H 2 0, 
or place it in the sun for some hours. Then rinse thoroughly in cold H a O 
and dry. 



96 ISTOKGANIC CHEMISTRY. 

free from chloride of lime (bleaching powder) by 
exposing it to the air in a saucer with a little H 2 0. 
The gas gradually passes off, being set free by the 
action of the C0 2 in the air, and the process may 
be hastened by adding a few drops of dilute acid. 
Chloride of lime is, therefore, of great service for 
disinfecting all places exposed to any noxious or 
unpleasant effluvia. Hospitals and rooms in which 
persons have died of a contagious disease are puri- 
fied by placing in them pans full of a mixture which 
is disengaging CI in large quantities. 

Compounds. — Hydrochloric Acid, Muriatic Acid, 
HC1. — CI and H form only this one compound, and it 
is produced whenever CI acts upon H or any sub- 
stance (e. g mj water, H 2 0) which contains H. If 
a lighted jet of H be brought into a jar of CI, the 
flame becomes whitish, the greenish CI disappears 
and a gas is formed which fumes as it escapes from 
the jar. 

HC1 is prepared by treating common salt (NaCl) 
with H 2 S0 4 : 

2 NaCl + H 2 S0 4 = Na 2 S0 4 + 2HC1. 

Properties. — It is an irrespirable, irritating, acid 
gas, with an intense attraction for H 2 0, which causes 
it to produce white fumes in the air. Water at 60° F. 
will absorb over 450 times its volume of the gas,* 
producing the liquid known as "Hydrochloric" or 

* The great solubility of HC1 in water can be shown by an experiment 
like that employed to demonstrate the solubility of NH 3 (see p. 36). If 
the water be colored with blue litmus, it will turn red as it comes into 
the bottle. 



THE HALOGENS. 
Fig. 47. 



97 




Preparing HC1. 

"Muriatic Acid. 1 ' This dissolves many metals with 
evolution of H and formation of chlorides. When 
pure it is colorless, but has ordinarily a yellow tinge, 
due to various impurities. Its tests are NH 3 , with. 
which it forms a white cloud of sal-ammoniac fumes, 
and silver nitrate, from which it precipitates AgCl. 
With HN0 3 it makes aqua regia,* or royal ivaier, so 
called because it dissolves Au, the "king of the 
metals " ; CI is set free, which, in its nascent state, 
attacks the Au and combines with it. 

Acids, Bases, and Salts. — We have seen that when 
gaseous NH 3 and HC1 come together, they unite with 
the formation of a white cloud. The same substance 
is produced when a solution of HC1 is poured into a 
solution of NH 3 , and may be obtained as a white 

* Boil HC1 in a test tube with, fragments of gold-leaf. They will not 
dissolve. Add a few drops of HN0 2 , and a yellow solution of gold chloride 
will be quickly formed. 



98 INORGANIC CHEMISTRY. 

powder by evaporating off the water. We have also 
seen that NH 3 or its solution turns red litmus blue, 
and that HC1 or its solution turns blue litmus red. 
Now, if, before pouring the h}^drochloric acid into 
the NH 3 solution, a little litmus be added to the lat- 
ter, it will be found that it remains blue until a 
certain quantity of the acid has been poured in, and 
that then the color suddenly changes to red. The 
point at which this change takes place may be hit so 
exactly that a drop of acid will turn the solution red, 
or a drop of NH 3 solution blue. At this point the so- 
lutions are said to have neutralized each other, since 
the distinctive character of each has disappeared. 

These solutions and the product of their action 
on each other may stand as types of those very im- 
portant classes of chemical compounds : the acids, 
the bases, and the salts. 

The Acids are generally sour* and turn vegetable 
colors — such as the infusion of blue litmus, or of 
purple cabbage f — to a bright red. This will be seen 
to be the case with even very dilute solutions of 
the three acids with which we have thus far become 
familiar, HN0 3 , H 2 S0 4 , and HC1. They all have the 
power of neutralizing NH 3 solution, and substances 
like it, with the formation of compounds in which 

* Certain acids, as well as certain bases, are insoluble in water, and 
hence have no taste. They, however, combine to form salts, which is their 
true test. 

t Paper tinged blue with a solution of litmus (a coloring matter ob- 
tained from certain lichens) should be constantly at hand in the laboratory, 
to determine the presence of a free acid. The same paper faintly reddened 
by vinegar, or any other acid, is a convenient test for the alkalies. The 
cabbage solution is made by steeping red cabbage-leaves in water, and 
straining the purplish liquid thus obtained. 



THEHALOGEXS. 99 

the place of the H of the acid has been taken by 
a metal or something which acts like a metal. All 
acids contain H which can be thus replaced. 

The Bases are substances which, like NH 3 solu- 
tion, have the power of neutralizing acids. They all 
contain a metal or something which acts like a 
metal. The alkalies* are bases which are soluble in 
water, have a soapy taste and feel, turn red litmus 
to blue, and red-cabbage solution to green, neutralize 
the acids and restore the colors changed by them. 
The property which the acids and bases thus hare 
of uniting with each other and destroying the chem- 
ical activity which either possesses alone is their dis- 
tinguishing trait. \ 

The Salts are substances formed by the neutral- 
ization of an acid by a base. They may be defined 
as acids in which the whole or part of the H has 
been replaced by a metal. Thus we have as salts 
of HN0 3 : KN0 3 , Pb2N0 3 , etc.; of HC1 : NaCl, CaCl 2 , 
etc.; of H 2 S0 4 : NaHS0 4 , Na 2 S0 4 , etc. 

Nomenclature of Acids and Salts. — The termina- 
tion ic is generally used in naming acids. Thus 



* The alkalies are compounds of H, O, and a metal. They are hence 
called hydroxides : as KOH (potassium hydrate, caustic potash), XaOH (so- 
dium hydrate). Ammonia solution is supposed to contain the compound 
XH*OH (ammonium hydroxide), in which XH 4 plays the part of a metal. 

t To a part of the purple-cabbage solution add a few drops of a solution 
of caustic potash : a green liquid will be produced. To another portion 
add a few drops of sulphuric acid : the solution will become red. Pour the 
red acid liquor into the green alkaline one, and stir the mixture : the red 
color at first disappears, and the whole remains green : but on adding it 
cautiously, a point is reached at which it assumes a clear blue color. 
There is then no excess of acid or alkali ; and on evaporation, a neutral 
salt, potassium sulphate, may be obtained. 



100 INORGANIC CHEMISTRY. 

HC1, hydrochloric acid; HN0 3 , nitric acid; H 2 S0 4 , 
sulphuric acid. All the acids except some of those 
in which members of the halogen group appear, 
contain 0, and in some cases these differ from 
each other only in the proportion of 0. Thus, there 
are two acids containing N: HN0 3 , and HN0 2 . To 
distinguish these the latter is called nitrous acid ; 
and in general, where there are two similar acids 
like these, the termination ous is employed in 
naming that containing the less proportion of 0. 
The salts derived from the acids that end in ic 
take the termination ate, and those from acids 
in ous, the termination ite. Thus from HN0 3 we 
have nitrates; from HN0 2 , nitrites. An exception 
to this rule is made in naming the salts of HC1 
and other halogen acids which contain no oxy- 
gen ; their salts are binary * compounds and take 
the termination ide. Thus we have NaCl, sodium 
chloride, etc. 

Bromine — named from its bad odor — is a poison- 
ous, volatile, deep-red liquid, with the general proper- 
ties of Cl.f It occurs only in combination, chiefly 
with Na in NaBr, which is principally found in sea- 
water. Br can be prepared from NaBr in the same 
way as CI from NaCl. With H, Br forms hydrobromic 
acid, HBr, which resembles HC1. With metals, bro- 
mides are formed (e.g. CdBr 2 ), which are used in 
photography and in medicine. 

* See Introduction, page 6. 

t Br is the only element, except Hg, which is liquid at ordinary tem- 
peratures. 



THE HALOGENS. 101 

Iodine is named from its beautiful violet-colored 
vapor. It is made from kelp (the ashes of sea-weed). 
Its salts are found in sea-water and in some mineral 
springs. It crystallizes in bluish-black scales, emits 
a smell resembling that of CI, sublimes* slowly, 
and is deposited in crystals on the sides of the bot- 
tle in which it is kept. I is sparingly soluble in 
H 2 0, but readily in ether or alcohol. It inflames 
spontaneously when in contact with phosphorus, f 
Its compounds with the metals, called the iodides, 
are remarkable for their variety and brilliancy of 
color. (See Appendix.) It stains cloth a yellowish 
tint, which may be removed by a solution of potas- 
sium iodide. Its test is starch, forming the blue 
iodide of starch.J I reveals the presence of this sub- 
stance in potatoes, wheat, etc.§ It is much used in 
medicine, especially in the treatment of bruises and 
skin diseases. 

Fluorine is the only element that will not unite 
with 0. It exists, in small quantities, in the 
enamel of the teeth. It is found in fluor spar 

* A body is said to sublime when it rises as vapor and condenses in the 
solid form ; when it condenses as a liquid it is said to distil. 

t Place on a clean, white dish a few scales of iodine and a bit of phos- 
phorus as large as a pea. They will soon combine, igniting the phosphorus 
and subliming a part of the iodine. 

X Mix one or two drops of a solution of potassium iodide with a little 
dilute starch mucilage ; no change of color will occur. Add a single drop 
of CI water to the mixture ; an immediate coloration will occur, owing 
to the combination of the CI with the K, while I is set free, which acts 
upon the starch. Add a little more chlorine water ; the color disappears, 
owing to the formation of chlorine iodide, which is without action on 
starch. 

§ Pour a few drops of a solution of iodine in alcohol on a freshly-cut 
potato. Blue specks will show the presence of starch. 



102 INORGANIC CHEMISTRY. 

(CaF 2 ), of which beautiful ornaments are made. 
In the free state it is a colorless gas of an odor re- 
sembling that of chlorine. It attacks all metals 
violently, combining with them to form fluorides. 
With H, it forms hydrofluoric acid (HF), noted 
for its corrosive action on glass. This eats out 
the silica or sand from the glass, and is there- 
fore used for etching labels on glass bottles and 
on shop windows. — Experiment: Powdered fluor 
spar is placed in a lead tray, and covered with 
dilute H 2 S0 4 . The heat of a lamp applied beneath, 
for a moment only, liberates the gas in white fumes 
very rapidly. The plate of glass is covered with 
wax, and the design to be etched is traced upon 
it with a sharp-pointed instrument. This is then 
laid over the tray, and the escaping gas soon etches 
the lines laid bare into an appearance like ground 
grass. A solution of HF in H 2 is often sold for 
this purpose. It is kept in lead or gutta-percha bot- 
tles, combines with H 2 with a hissing sound, like 
red-hot iron, and must be handled with care, as even 
a minute drop will sometimes produce obstinate blis- 
ters and sores. 



SULPHUR. 103 

SULPHUR. 

Symbol, S. . .Atomic Weight, 32 . . . Specific Gravity, 1.96-2.05. 

Sources. — S is found native in volcanic regions. 
It is mined near Mount iEtna in great quantities. 
United with the metals it forms sulphides, known 
as cinnabar, iron pyrites, galena, blende, etc. Com- 
bined with and metals it exists in gypsum (plas- 
ter), heavy spar, and other sulphates. It is found in 
the hair, and many dyes contain Pb which unites 
with the S, and forms a black compound that stains 
the hair. It is contained in eggs, and so tarnishes 
our spoons by forming a sulphide of silver. It is 
always present in the flesh, and hence manifests 
itself in our perspiration. In commerce it is sold as 
brimstone, formed by melting S and running it into 
molds ; also as flowers of sulphur, obtained by sub- 
limation. 

Properties. — It is insoluble in H 2 0, and hence 
tasteless. Its solvents are carbon disulphide (CS 2 ), 
oil of turpentine, and benzene. It is a non-conductor 
of heat, and crackles when we grasp it with a warm 
hand. It may be obtained in several allotropic forms : 
1st, octahedral crystals; 2d, prismatic crystals; 3d, an 
amorphous (without form) or uncrystallized state ; 
and 4th, a viscid condition. The last is the most 
interesting. — Example : When S is melted, and then 
heated more strongly, it changes to a thick, viscid, 
dark-colored liquid resembling molasses. If this is 
poured into cold water, it becomes elastic like India 



104 



INORGANIC CHEMISTRY. 



rubber. S is very much like oxygen in its power to 
unite readily with most of the elements. 

Uses. — On account of its ready inflammability, S 
is employed in the making of matches and gun- 
powder, but its chief consumption is in the produc- 
tion of H 2 S0 4 . 

Compounds. — Sulphur Dioxide, S0 2 , an irrespirable, 
suffocating gas, is formed by S burning in the air, 
as in the lighting of a match. It is prepared for 
experiments by treating copper with strong H 2 S0 4 . 
On heating, S0 2 is evolved and may be collected like 
CI by displacement. The action of the acid on the 
copper is represented thus : 

Cu + 2H 2 S0 4 = CuS0 4 + 2H 2 + S0 2 . 

S0 2 is more than twice as heavy as air. It is readily 
soluble in water, forming a solution which is be- 
lieved to contain H 2 S0 3 , sulphurous acid. When 

this is neutralized by bases it 
yields salts called sulphites. 
S0 2 will not support com- 
bustion. 

Uses. — S0 2 is made in large 
quantities for the purpose 
of manufacturing sulphuric 
acid. It is used for bleach- 
ing silk, straw, and woolen 
fabrics, which are destroyed by 
CI. Its action is very different 
from that of CI, and depends upon the power it has 
of withdrawing from substances or reducing them, 



Pig. 48. 




Bleaching by S0 2 



SULPHUR. 105 

as it is called. This takes place in the presence of 
moisture, and the result is that the S0 2 with H 2 
and the forms sulphuric acid, H 2 S0 4 . The reducing 
action of S0 2 is made use of in the manufacture cf 
paper, to destroy the excess of CI after bleaching : 

S0 2 + Cl 2 + 2H 2 = H 2 S0 4 + 2HC1. 

S0 2 is called on this account an "anti-chlor." 

The bleaching effected by S0 2 is not permanent 
like that by CI. The color is often restored by ex- 
posure to the air or by alkalies. S is also frequently 
employed to check fermentation, as when it is burned 
in a barrel before filling with new cider. 

Sulphur Trioxide, S0 3 , may be prepared by the 
oxidation of S0 2 in the presence of platinum sponge. 
It is often called sulphuric anhydride* If Nord- 
hausen acidf be heated, the vapors may be con- 
densed in a mass of silky, crystalline fibers of S0 3 . 
This will show no acid reaction, will not redden blue 
litmus-paper, and, if the fingers are dry, can be 
molded like wax. If it be dropped into H 2 0, it will 
hiss like a red-hot iron, and forming H 2 S0 4 , will ex- 
hibit all the properties of that corrosive substance. 

Sulphuric Acid, Oil of Vitriol, is the king of the 
acids. It is of the utmost importance to the manu- 
facturer and chemist, as it is used in the preparation 
of nearly all other acids, and many valuable com- 
pounds. 

* An anhydride (without water) is a substance which, when dissolved 
in H 2 0, will unite with its elements and form an acid. 

t So named from the G-erman town near which it was formerly made 
by the distillation of green vitriol (iron sulphate). 



106 



INORGANIC CHEMISTRY. 



Fig. 49. 




Making 
H 9 S0 4 . 



Preparation. — H 2 S0 4 is such a strong acid that it 
can not be made by the action of some other acid 
on its salts, the sulphates, as HN0 3 is made from 
nitrates and H CI from chlorides. It is always made by 
oxidizing sulphurous acid, or what comes to the same 
thing, oxidizing S0 2 in the presence of moist- 
ure. If we burn a little S in a bottle, it will 
soon become filled with S0 2 . Mtric acid, it 
will be remembered, easily parts with its 0. 
So if we stir the S0 2 with a swab wet in 
aqua fortis, we shall quickly see the familiar 
N0 2 fumes, indicating that the acid has 
been decomposed and has given up 0. Add 
a little water and shake the jar thoroughly. 
On testing the liquid with a few drops of a solution 
of barium chloride, a beautiful white precipitate will 
prove the presence of H 2 S0 4 .* 

The Manufacture of Sulphuric Acid on a large 
scale is based on the principle of the preceding illus- 
tration. The process is facilitated by the curious 
fact that nitric oxide (NO) has the property of act- 
ing as a carrier of between the common air and 
H 2 S0 3 , whereby it can oxidize an almost indefinite 
quantity, thus forming H 2 S0 4 . S is burned in a cur- 
rent of air in furnaces A, A. In the stream of 
heated gas is suspended an iron pot, 6, charged with 
a mixture of sodium nitrate and H 2 S0 4 . Vapors of 
HN0 3 are thus set free, and these pass on mixed 



* The reaction in making the acid may be thus expressed : 
2HN0 3 + 3S0 2 + 2H 2 = 3H 2 S0 4 + 2NO. 
The NO is at once converted into 1ST0 2 by the O of the air in the bottle. 



S ULPH U R . 



10" 



with SO 2 and excess of atmospheric air. The min- 
gled gases pass into immense chambers, i\ of sheet 



Fig. 50. 




Manufacture of H a S0 4 . 

lead. A shallow layer of H 2 0, d, covers the floor, 
and the intermixture and chemical action of the 
gases are further favored by the injection of jets of 
steam, e, supplied from the boiler. G. 

The chemical action which ensues may be ex- 
plained as follows :— The nitric acid is quickly reduced 
to nitric oxide, NO. This takes up an atom of 
from the air, becoming N0 2 , and flies back to the 
S0 2 which, with a molecule of H 2 becomes H 2 S0 4 . 
a molecule of sulphuric acid. The NO once more 
seeks the air and returns laden with for the S0 2 . 
The weak sulphuric acid which collects on the floor 
is drawn off and condensed by evaporation in lead 
pans, and finally, when it begins to corrode the lead, 
in platinum or glass stills. It is then put in large 



108 



INORGANIC CHEMISTRY. 
Fig. 51. 




Making H 2 SO*. 

bottles packed in boxes called carboys, when it is 
ready for transportation. 

Properties. — It is a heavy, oily liquid, without 
odor, and when pure, colorless. The commercial acid 
is slightly colored by impurities. Its affinity for 
moisture is most remarkable. If exposed in an open 
bottle it gradually absorbs water from the air, and 
increases in bulk, sometimes even doubling its weight. 
It blackens wood and other organic substances, by 
taking away their H and and leaving the C* 
When mixed with H 2 0, it produces much heat; 4 
parts of acid to 1 of H 2 will boil a test-tube of 
water, f It commonly contains lead, which falls as a 

* Strong oil of vitriol poured on a little loaf-sugar will convert it into 
black charcoal. Sugar consists of C, H, and O, and gives up the H and O 
to satisfy the acid. 

t In mixing H 2 SO, and H 2 0, the H 2 S0 4 should always t>e poured into 
the H 2 (and not the H 2 into the H 2 SO.) slowly and with constant stirring. 



SULPHUE. 



109 



milky precipitate (PbS0 4 ) when the acid is diluted. 
It is the strongest of the acids, and will displace the 
others from their compounds. It stains cloth red, 
but the color can be restored by an alkali, if applied 
immediately. Its test is barium chloride, which forms 
a heavy white precipitate. In this way a drop of 
H 2 S0 4 can be detected in a quart of H 2 0. 



Fig. 52. 




Preparing H a S. 

Hydrogen Sulphide, H 2 S, Sulphuretted Hydrogen. 
Sulphydric Acid.— This gas is produced in the decay 
of various organic substances, and is always found 
near cess-pools, drains, and sinks, turning lead paint 
black and emitting a disagreeable smell. It gives 
the characteristic odor to the mineral waters of Avon, 
Clifton, Sharon, and other celebrated sulphur springs. 
It is prepared by the action of dilute H 2 S0 4 upon 
ferrous sulphide (FeS). The reaction is as follows: 

FeS + H 2 S0 4 = FeS0 4 + H 2 S 



110 XJSTORGANIC CHEMISTRY. 

H 2 S has the disgusting odor of rotten eggs. It 
burns with a pale blue flame, producing S0 2 and 
H 2 0. It is very poisonous. The gas as well as its 
solution in H 2 are much used in the analytical labo- 
ratory to precipitate many of the metals as sulphides. 
Its test is lead acetate (sugar of lead), with which 
it forms black PbS (lead sulphide). 

Carbon Disulphide, CS 2 , is produced by passing 
the vapor of S over red-hot coals. It is a volatile, 
colorless liquid. The fact that a yellow, odorless 
solid thus unites with a black, odorless solid to form 
such a colorless, odoriferous liquid, illustrates very 
finely the transformations which may be effected 
by chemical affinity. CS 2 readily dissolves S, P, 
and I. It is largely used as a solvent for caout- 
chouc and as a means for recovering from wool 
the oil and fats with which they are treated. It is 
a powerful refractor of light, and is used for filling 
hollow, glass prisms employed in experiments with 
the solar spectrum. In its combustion it unites with 
0, forming C0 2 and S0 2 . 



PRACTICAL QUESTIONS. 

1. If chlorine water stands in the sunlight for a time, it will only red- 
den a litmus-solution. Why does it not bleach it? 

2. Why do tinsmiths moisten with HC1, or sal-ammoniac, the surface 
of metals to be soldered? 

3. How much HC1 can be made from 25 kilos of common salt? 

4. What weight of NaCl would be required to form 25 kilos of HC1. 

5. HC1 of a specific gravity of 1.2 contains about 40 per cent, of the 
gas. This is very strong commercial acid. What weight could be formed 
by the HC1 gas produced in the reaction named in the preceding problem? 

6. What is the difference between sublimation and distillation? 

7. Why do eggs discolor silver spoons? 



VALENCE. Ill 

8. Explain the principle of hair-dyes. 

9. Is it safe to mix oil of vitriol and water in a glass bottle ? 

10. What is the color of a sulphuric acid stain on cloth? How would 
you remove it? 

11. What causes the milky look when oil of vitriol and water are 
mixed ? 

12. What is the chemical relation between animals and plants? Which 
perform the office of reduction, and which of oxidation? 

13. How many pounds of S are contained in a cwt. of H 2 S0 4 ? 

14. How much O and H 2 are needed to change a ton of S0 2 to H 2 S0 4 ? 

15. How much O in a pound of H 2 S0 4 ? 

16. State the analogy between the compounds of O and S. 



VALENCE 



In the Introduction it was stated that atoms had 
a certain property, in virtue of which each could 
hold a definite number of other atoms in combina- 
tion, and that this property was called valence. 

If we now review the formulas of some of the 
compounds with which we have become familiar, 
we shall be able to see more clearly just what is 
meant by this statement. We have had the follow- 
ing binary compounds of H : 

HC1, H 2 0, NH 3 , CH 4 . 

We see from these that the CI, 0, N, and C atoms 
differ from each other in respect to the number of 
H atoms which they hold in combination ; holds 
twice as many as CI ; N three times as many, and 
C four times as many as CI or twice as many as 0. 
No atom can hold a less number of any other atoms 
than CI or H. That is to say, they have the property 
of valence in the lowest degree. On this account CI, 



112 INORGANIC CHEMISTRY. 

H, and other atoms which can hold but one of them 
are called univalent ; atoms which, like 0, can hold 
two of H or two unit atoms in combination, are 
called bivalent ; atoms like N, which can hold three 
unit atoms, are called trivalent; and atoms like C, 
which hold four, are called quadrivalent. Thus, F is 
seen to be univalent (HF) ; S, bivalent in H 2 S and 
quadrivalent in S0 2 (since each atom is equivalent 
to two atoms of H); P trivalent in PH 3 . 

When the H of acids is replaced by metals in 
the formation of salts, a univalent metal may take 
the place of each atom of H, as in NaCl, NaN0 3 , 
Na 2 S0 4 ; or a bivalent metal may take the place 
of two atoms of H, as in MnCl 2 , Cu2N0 3 , PbS0 4 ; and 
so on. 

Acids which contain but one atom of replaceable 
H are called monobasic acids. Such acids can form 
only one kind of salt with the same metal. Acids 
which have two {bibasic) or more (tribasic, etc.) 
replaceable atoms of H can form two or more classes 
of salts, in some of which only a part of the H is 
replaced by a metal; in others, all. Thus, H 2 S0 4 , 
a bibasic acid, forms Na 2 S0 4 , and NaHS0 4 . The 
former is called normal sodium sulphate, the lat- 
ter acid sodium sulphate, because it still contains 
replaceable H. 



PHOSPHORUS. 



113 



by 



PHOSPHORUS. 
Symbol, P Atomic Weight, 31 Specific Gravity, 1,83, 

The name Phosphorus signifies light-bearer, given 
because this substance glows in the dark. It was 
called by the old alchemists "the son of Satan."* 

Occurrence. — It exists in combination with and 
metals in a number of minerals and rocks, and by 
their decay passes into the soil, is taken up 
plants, is then stored in their 
seeds (wheat, corn, oats, etc.), 
and finally passes into our 
bodies. As calcium phosphate 
(Ca 3 2P0 4 , phosphate of lime), 
it is a prominent constituent 
of our bones, f Phosphorus is 
so necessary to the operation 
of the brain that a saying 
has become current, "Without 
phosphorus, no thought." \ 

Preparation. — It is prepared in considerable quanti- 



Pig. 53. 




Manufacture of Phosphorus. 



* The following singular event is said to have occurred many years 
before the reputed discovery of phosphorus by Brandt in 1669. A certain 
Prince San Severo, at Naples, exposed some human skulls to the action of 
several re-agents, and then to the heat of a furnace. From the product he 
obtained a substance which burned for months without apparent loss of 
weight. San Severo refused to divulge the process, as he wished his family 
vault to be the only one to possess a "perpetual lamp" the secret of which 
he considered himself to have discovered. 

+ "Of phosphorus every adult person carries enough (1% lbs.) about 
with him in his body to make at least 4,000 of the ordinary two-cent 
packages of friction matches, but he does not have quite sulphur enough 
to complete that quantity of the little incendiary combustibles."— Nichols' 
Fireside Science. 

% See an article by Prof. Atwater in The Century, for June, 1887, page 249. 



114 inorganic chemistry. 

ties from bones. These are first calcined to white- 
ness to burn out the animal matter, then treated 
with H 2 S0 4 , which changes the calcium phosphate 
into a compound which is reduced at a high tem- 
perature by C. The phosphorus which distils as a 
vapor is condensed under H 2 0. 

Properties. — It is a waxy, translucent solid, at all 
temperatures above 0°C. emits a feeble light, melts 
at 44° C, and ignites at a little higher temperature. 
It should be handled with the utmost care, always 
kept and cut under H 2 0, never used except in very 
small quantities, and never held in the hand. Its 
burns are deep and dangerous. It is poisonous, and 
its vapor produces horrible ulcerations of the jaw- 
bone in workmen who use it carelessly. 

Red Phosphorus. — Heated for several hours at a 
temperature of about 2 50°C, in a close vessel, the 
melted phosphorus changes into a brick-red solid, 
and loses all its former properties. It is now insolu- 
ble in CS 2 , which can be used to dissolve out every 
trace of the common form. Its specific gravity is 
increased to 2.14. It can be handled with impunity, 
carried in the pocket like so much snuff, and even 
heated to nearly 2 60° C. without taking fire. At a 
little over 260° C, however, it changes into the com- 
mon form and bursts into a blaze. 

Uses. — Matches. — The principal use of phosphorus 
is in the manufacture of matches. 1. The Lucifer 
Match. — The bits of wood are first dipped in melted 
S and dried ; then in a paste of phosphorus, niter, 
and glue, which completes the process. The object 



PHOSPHORUS. 115 

of the niter is to furnish to quicken the combus- 
tion. Instead of this, potassium chlorate is some- 
times used ; it can be recognized by a crackling 
sound and jets of flame when ignited. The tips are 
colored by red-lead, or Prussian blue, mixed in the 
paste. When a match is burned, the reaction is as 
follows : first, the phosphorus ignited by friction 
burns, forming P 2 5 ;* this produces heat enough 
to inflame the S, which makes S0 2 : lastly, the 
wood takes fire, and forms C0 2 and H 2 0. Thus there 
are four compounds produced in the burning of a 
single match. 

2. The Safety Match. — The pieces of wood are 
dipped into melted paraffine (see p. 190) and dried. 
They are then capped with a paste of potassium 
chlorate, sulphide of antimony, powdered glass, and 
gum-water. They ignite only when rubbed on a sur- 
face covered with a mixture of red phosphorus and 
powdered glass. 

Phosphorescence is the property of emitting light, 
without the high temperature which accompanies 
ordinary burning. TTe have seen that P glows in 
the dark, but it is by no means the only substance 
which presents this phenomenon. The luminous ap- 
pearance of putrefying fish and decayed wood is 
well known. The latter is sometimes called "fox- 

* The burning phosphorus produces a very luminous flame, because of 
the reflection of light from the dense vapor (P 2 5 ). The following experi- 
ment is very suggestive in this connection : Ignite a bit of phosphorus 
placed upon a sheet of white paper. The paper will be blackened just 
where the phosphorus lay, but will not take fire ; and after the flame is 
extinguished, one can write upon it with pen and ink, close to the edge of 
the charred portion. 



116 



INORGANIC CHEMISTRY, 



fire." The " glow-worm's fitful light" is associated 
with our memory of beautiful summer evenings. In 
the West Indies, fire-flies are found that emit a green 
light when resting, and a red one when flying. They 
are so brilliant that one will furnish light enough 

Fig. 54. 




Preparation of PH 3 



for reading. The natives wear them for ornaments 
on their bonnets, and illuminate their houses by 
suspending them as lamps. The ocean occasionally 
takes on strange colors, and the sailor finds his vessel 
plowing at one time apparently a furrow of fire, and 
at another one of liquid gold. The water is all 
aglow, and the flames seem to leap and dance with 






ARSENIC. 117 

the waves or the motion of the ship. The phe- 
nomenon is produced by multitudes of animalcules 
which frequent certain seas.* 

Compounds. — Hydrogen Phosphide, PH 3 , Pltos- 
phuretted Hydrogen, is a poisonous gas, remarkable 
for its disgusting odor, for igniting spontaneously 
on coming to the air, and for the singular beauty 
of the rings formed by its smoke. It is prepared by 
heating in a retort a strong solution of potash con- 
taining a few bits of phosphorus. It has been 
thought by some that the Will-o'-the-wisp, Jack-o'- 
the-lantern, etc., as seen near grave-yards and in 
swampy places, are produced by this gas coming 
off from decaying substances, and igniting as it 
reaches the air. 



ARSENIC. 
Symbol, As Atomic Weight, 75 . . . Specific Gravity, 5.7. 

Volatilizes without fusion at about U50° C. 

As is a brittle, steel-gray metal, f commonly sold, 
when impure, as cobalt. \ If heated in the open air 

* Many substances, after having been exposed to the light, will shine 
for some time when removed into the darkness. Thus, a dial coated with 
the so-called Luminous Paint (calcium sulphide) will show the time at night. 

t Arsenic very much resembles phosphorus in its general properties, and 
is therefore classified with it, but it conducts electricity moderately, and has 
a high brilliancy. It is intermediate between the non-metals and the 
metals. 

t Cobalt is a reddish- white metal, found in combination with arsenic. 
Co received its name from the miners, because its ore looked so bright that 
they thought they would obtain something valuable ; but when, by roast- 



118 INORGANIC CHEMISTRY. 

it gives off the odor of garlic, which is a test 
of As. 

Arsenic Trioxide, As 2 3 — This is the well-known 
"ratsbane" and is sometimes sold as simply " arsenic," 
or "white arsenic." 

Preparation. — It is made in the Harz and else- 
where, by roasting arsenical ores at the bottom of a 
tower, above which is a series of rooms through 
which the vapors ascend, and pass out at a chimney 
in the top. The As burns, forming As 2 3 , which col- 
lects as a white powder on the walls and floors of 
the chambers above.* 

Properties.— "Arsenic" is slightly soluble in H 2 0, 
and has a weak metallic, faintly sweetish taste. It 
is a powerful poison, doses of two or three grains 
being fatal, although an over-dose acts as an emetic. 
It is an antiseptic, and so in cases of poisoning 
frequently attracts attention by the preservation 
of parts of the body for a considerable time after 

ing, it crumbled to ashes, they believed themselves mocked by the evil 
spirit (Kobolt) of the mines. The oxide of cobalt makes a beautiful blue 
glass, which, when ground fine, is called smalt. It is used for tinting paper, 
and by laundry women to give the finished look to cambrics, linen, etc. 
Its impure oxide, called zaffer, imparts the blue color to common earthen- 
ware and porcelain. The chloride (CoCl 2 ) is used as a sympathetic ink. 
Letters written with a dilute solution of it are invisible when moist with 
the H 2 absorbed from the air, but on being dried at the stove, again 
become blue. If the paper be laid aside the writing will disappear, but 
may be revived in the same manner. A winter landscape may be drawn 
with India-ink, the leaves being added with this ink. On being brought 
to the fire it will bloom into the foliage of summer. 

* Its removal is a work of great danger. The workmen are entirely 
enveloped in a leathern dress and a mask with glass eyes ; they breathe 
through a moistened sponge, thus filtering the air of the fine particles of 
arsenic floating through it. Yet, in spite of all these precautions, they 
rarely live beyond forty. 



ARSENIC. 



119 



the murder has been committed. The antidote is 
milk or white of egg.* 

Marsh's Test. — There is no other poison which is 
so easily detected. Prepare a flask for the evolution 
of H. Ignite the jet of gas, and hold in the flame a 

Pig. 55. 




MarsWs Test. 

cold porcelain dish. If it remains untarnished, the 
materials contain no As. JSTow pour in through the 
funnel-tube a few drops of a solution of As;f the 
color of the flame will be seen to change almost 

* The exact chemical antidote is hydrated ferric oxide. In this, as in 
most other cases of poisoning, where the antidote is not at hand, an emetic 
should be taken at once— a tea-spoonful of mustard in a glass of warm 
water, or even a quantity of soap-suds. (See "Physiology," page 209.) 

t This is made by dissolving a little As 2 3 in HC1. 



120 INORGANIC CHEMISTRY. 

instantly, and a copious deposit of As will be formed 
on the dish. If the tube through which the gas is 
passing be heated (see fig. 55), a metallic mirror of 
arsenic will appear just beyond the heated place.* 
The gas formed in this experiment — arseniuretted 
hydrogen — is very poisonous indeed, and the utmost 
care should be used to prevent its inhalation. 

Arsenic-Eating. — It is said that the peasants in a 
portion of Styria are accustomed to eat As, both fast- 
ing and as a seasoning to their food. A very minute 
portion will warm, stimulate, and aid in climbing 
lofty mountains. The arsenic-eaters are described as 
plump and rosy, and it is said that the young people 
resort to this dangerous substance, as a species of 
cosmetic. They begin with small doses, which are 
gradually increased; but if the person ceases the 
practice, all the symptoms of arsenic poisoning im- 
mediately appear. Horse-jockeys sometimes feed 
arsenic to their horses to improve their flesh and 
speed. 



BORON. 

Symbol, B ^ om i c Weight, 11. 

Boron is found in nature in combination with 
H and as boric acid, and as borates. Boric acid is 

* In a case of poisoning the contents of the stomach would, of course, 
be substituted for the solution of As, the organic matter first being de- 
stroyed, and other tests besides these would be employed. We can imagine 
with what care a chemist would conduct the examination, and with what 
intense anxiety he would watch the porcelain dish as the flame played 
upon it, hesitating, and dreading the issue, as he felt the life of a fellow- 
being trembling on the result of his experiment. 



BORON. 



121 



abundant in the volcanic districts of Tuscany.* 
Along the sides of the mountains, series of basins 
are excavated and filled with cold water from the 
neighboring springs. Into these basins the jets of 
steam, charged with boric acid, are conducted. The 
H 2 absorbs the acid, and itself becomes heated to 
the boiling-point. It is then drawn off into the next 

Fig. 56. 




Preparing Boric Acid in Thibet, 



lower basin. This process is continued until the 
bottom one is reached, when the solution runs into 
leaden pans heated by the steam from the earth; 
here the H 2 is evaporated, and the boric acid col- 
lected. 

Borax (Na 2 B 4 7 , 10H 2 O) is a salt of this acid. It 
is a natural production, formerly obtained by the 

* Throughout an area of nearly thirty miles, is a wild, mountainous 
region, of terrible violence and confusion. The surface is ragged and blasted. 
Every- where there issue from the ground jets of steam, filling the air 
with offensive odors. The earth itself shakes beneath the feet, and fre- 
quently yields to the tread, ingulfing man and beast. " The waters below 
are heard boiling with strange noises, and are seen breaking out upon the 
surface. Of old, it was regarded as the entrance to hell. The peasants pass 
by in terror, counting their beads and imploring the protection of the 
Virgin." 



122 INORGANIC CHEMISTRY. 

drying of certain lakes in Thibet, but since found 
abundantly in California and Nevada. When dis- 
solved in alcohol, boric acid gives to the flame a 
peculiar green tint. This is an easy test of the pres- 
ence of this acid. In order to make this test with 
borax, H 2 S0 4 must be added to set the boric acid 
free, for the salts of boric acid do not color the 
flame. The salt is employed in welding. It dissolves 
the oxide of the metal, and keeps the surface bright 
for soldering. It has mild cleansing properties due 
to its power of dissolving oils and resinous substances 
and is used in washing.* 



SILICON. 

Symbol, Si,.,. Atomic Weight, 28 .... Specific Gravity, 2.49, 

Occurrence. — Silicon is found in combination with 
as silica (silicic anhydride, Si0 2 ), commonly called 
silex or quartz. So abundant is this oxide that it 
probably comprises nearly one half of the earth's 
crust. (See "Geology," p. 40.) It forms beautiful 
crystals and some of the most precious gems. When 
pure, it is transparent and colorless, as in rock 

* Borax is extensively used in "blow- pipe analysis." When melted with 
chromium oxide, it gives an emerald green ; with cobalt oxide, a deep blue ; 
with copper oxide, a pale green; and with manganese oxide, a violet.— The 
Salt, or Alkali, Marshes of Nevada, contain extensive deposits of sodium 
chloride, sodium carbonate, sodium borate, calcium borate, etc. There are 
hundreds of acres covered to a depth of nearly two feet with crude, semi- 
crystalline borax. See an article entitled "Borax in America," in the 
Popular Science Monthly, July, 1882. 



SILICON. 123 

crystal. Jasper, amethyst, agate, chalcedony, blood- 
stone, chrysoprase, sardonyx, etc., are all common 
flint-stone or quartz, colored with some metallic 
oxide. The opal is only Si0 2 and H 2 0. Sand is 
mainly fine quartz, which, when hardened and ce- 
mented, we call sandstone. Yellow or red sand is 
colored by iron-rust. 

Properties of Si0 2 . — It is tasteless, odorless, and 
colorless. It seems very strange to call such an inert 
substance an anhydride ; yet it unites with the al- 
kalies, neutralizes their properties, and forms a large 
class of salts known as the silicates, which are found 
in the most common rocks. — Example : feldspar, 
found in granite. 

Silica in Soil and Plants. — Silica is insoluble in 
H 2 0, unless it contains some alkali. When the sili- 
cates, so abundant in rocks, disintegrate and form 
soil, the alkali and silica are both dissolved in the 
water, and taken up by the roots of plants. We see 
the silex on the surface of scouring-rushes and 
sword-grass, which cut the fingers if handled care- 
lessly. It gives stiffness to the stalks of wheat and 
other grains, and produces the hard, shiny surface of 
bamboo, corn, etc. 

Petrifaction. — Certain springs contain large quan- 
tities of some alkaline carbonate ; their waters, there- 
fore, dissolve silica abundantly. If we place a bit of 
wood in them, as fast as it decays, particles of silica 
will take its place and thus petrify the wood. The 
wood has not been changed to stone, but has been 
replaced by stone. 



124 INORGANIC CHEMISTRY. 

Compounds.— The Silicates.— Glass* is a mixture 
of several silicates. There are four varieties used in 
the arts. 1. Window or plate glass is composed of 
silicates of calcium and sodium. It is made by heat- 
ing white sand, sal-soda, and lime in clay crucibles 
for about forty-eight hours, when the materials fuse 
and combine into a double silicate. The Ca hardens 
and gives luster; the Na renders the glass fusible. 

2. Bohemian glass consists of silicates of calcium 
and potassium. It can withstand a very high tem- 
perature without softening, and resists chemical ac- 
tion ; hence it is of great importance to the chemist. 

3. Flint-glass \ or crystal contains silicates of potas- 
sium and lead. The latter is used in large quantities 
and produces a soft, lustrous glass, which can be 
ground into imitation gems, tableware, chandelier 
pendants, prisms, etc. 4. Green bottle-glass is made 
of silicates of calcium, sodium, aluminium, and iron. 
The last gives the opaque green of the common junk 
bottle. 

* Q-lass was known to the ancients. Hieroglyphics, that are older than 
the sojourn of the Israelites in Egypt, represent glass-blowers at work, 
much, after the fashion of the present. In the ruins of Nineveh, articles 
of glass, such as vases, bowls, etc., have been discovered. Mummies, three 
thousand years old, are adorned with glass beads. The inventor is not 
known. Pliny tells us that some merchants, once encamping on the sea- 
shore, found in the remains of their fire bits of glass, formed from the 
sand and ashes of the sea- weed by the heat; but this is impossible, as an 
open fire is not sufficient to melt these materials. In the fourth century 
b.c, the glass-works at Alexandria produced exquisite ornaments, with 
raised figures beautifully cut and gilded. But in the twelfth century a.d., 
glass was still so costly in England that glass windows were thought very 
magnificent ; and, as late even as about 1500, when the great Earl of North- 
umberland left one of his houses for a time, he was careful to have the 
glass of the windows taken down and packed for safe-keeping. 

t So called because pulverized flint was formerly used for sand. 



SILICON. 125 

Coloring Glass. — A small quantity of some metal- 
lic oxide melted with the glass furnishes any tint 
desired: Co gives a beautiful sapphire blue; Au or Cu, 
a ruby-red; Mn, a violet; U, a yellow; As, a soft white 
enamel, as in lamp-shades; and Sn, a hard enamel, 
as in watch-faces. 

Annealing Glass. — If the glass utensils were cooled 
immediately, they would be found extremely brittle, 
and would drop to pieces in the most unaccountable 
way. The heat of the hand or a draft of cool air 
would sometimes crack off the thick bottom of a 
tumbler. They are therefore cooled very gradually 
for days, which allows the particles to assume their 
natural place, and the molecular attractions to be- 
come equalized.* 

Ornamental Ware. — Venetian balls or paper 
weights are made by arranging bits of colored glass 
in the form of fruits, flowers, etc., and then, insert- 
ing them in a hollow globe of transparent glass, still 
hot, the workman draws in his breath, and the 
pressure of the air above collapses the globe upon 
the colored glass, and leaves a concave surface in 
the opposite side of the weight. The lens form 
always magnifies the size of the figures within. 

Tubes and Beads. — In making glass tubing, the 
workman inserts his iron blowing-tube in a pot of 
melted glass, and gathers upon the end a suitable 
amount ; drawing this out, he blows into the tube, 
swelling the glass into a globular form. Another 

* This principle is beautifully illustrated by the toy known as the 
"Prince Rupert's Drop." (See "Physics," p. 46.) 



126 INORGANIC CHEMISTRY. 

dip into the pot and another blow increase its size, 
until at last a second workman attaches an iron rod 
to the other end. The two men then separate at a 
rapid pace. The soft glass globe diminishes in size 
as it lengthens, until at last it hangs between them 
a glass tube of a hundred feet in length, and perhaps 
only a quarter of an inch in diameter. 

For making beads, glass tubes are cut in short 
pieces, and then worked about in a mixture of wet 
ashes and sand, until they are filled. They are next 
put with loose sand in a cylinder rapidly revolving 
over a hot furnace. The heat softens the glass, but 
the mixture within presses out the sides, and the 
sand grinds the edges, until at last the beads become 
round and perfect, and are taken out ready for 
market. 



THE METALS. 



THE METALS OF THE ALKALIES, 



K, Na> Li, Rb, Cs. 



POTASSIUM 
Synjbol, K. , , .Atonjic Weight, 39.1, . , .Specific Gravity, 0.87. 

Source. — K occurs widely distributed in various 
rocks, which by their decomposition furnish it to the 
plants.* When these are burned it remains as potas- 
sium carbonate in the ashes. It also is found in 
considerable deposits in the form of chloride and 
nitrate. 

Preparation. — This metal was discovered by Sir 
Humphry Davy, in 1807. On passing the current 
of a powerful electric battery through potash, the 
globules of the K appeared at the negative pole. 
The metals Na, Ba, Sr, and Ca, were afterward sepa- 
rated in the same manner. This discovery constituted 
a most important epoch in chemistry. K is now 

* " An acre of wheat, producing twenty-five bushels of grain and 3,000 
lbs. of straw, removes about 40 lbs. of potash in the crop. An acre of corn, 
producing 100 bushels, removes in kernel and stalk 150 lbs. of potash and 
80 lbs. of phosphoric acid. An acre of potatoes, yielding 300 bushels, will 
remove in tubers and tops 400 lbs. of potash and 150 lbs. of phosphoric 
acid. A pound of wheat holds a quarter of an ounce of mineral sub- 
stances, and a pound of potatoes one eighth of an ounce."— Nichols. 



128 INORGANIC CHEMISTRY. 

prepared by decomposing potassium carbonate by 
means of charcoal in iron bottles, at an intense heat. 
The green vapors of K distil and are condensed in 
receivers of naphtha, and CO passes off as a gas, 
K 2 C0 3 + 2C = 2K + 3CO. It is a difficult and dangerous 
process. The vapor takes fire instantly on contact 
with air or water. It also absorbs CO, and the com- 
pound, if kept, becomes powerfully explosive. To 
prevent this danger, the K is immediately redistilled. 

Properties. — K is a silvery - white metal, soft 
enough to be spread with a knife, and light enough 
to float like cork. Its affinity for is so great that 
it is always kept under the surface of naphtha, 
which contains no 0. K, when thrown on H 2 0, de- 
composes it with great energy (see page 38). 

Compounds. — Potassium oxide, K 2 0, has so great 
an affinity for H 2 that the anhydrous form is rarely 
prepared. Its hydrate, potassium hydroxide, KOH,* is 
a white solid made from potassium carbonate by the 
action of slaked lime. It is the most powerful alkali. 
It neutralizes the acids, and turns red litmus to blue. 
It is used to cauterize the flesh, and is hence com- 
monly called " caustic potash." It dissolves the cuticle 
of the finger which touches it, and so has an unctuous 
feel. It unites with grease, forming soft-soap, in the 
manufacture of which it is extensively used. 

Potassium Carbonate, K 2 C0 3 , Pearlash, " Carbonate 
of Potash," is obtained in the following l manner : 
Potash exists in plants, combined with various acids, 
such as tartaric, malic, oxalic, etc. When the wood 

* K 2 + H 2 0=2KOH, or 2 molecules of potassium hydroxide. 



POTASSIUM. 129 

is burned, the organic salts are decomposed by the 
neat, and K remains chiefly as K 2 C0 3 . The ashes are 
then leached and the lye is evaporated, when the 
K 2 C0 3 crystallizes. This forms the " potash" of com- 
merce. When refined, it is called "pearlash." 
Where wood is abundant, immense quantities are 
burned solely for this product.* 

Large quantities of potash are also obtained from 
potassium chloride and sulphate, by a process which is 
exactly like that described on p. 135 for making soda. 
A considerable amount is also obtained from wool fat 
and from the waste in beet sugar manufacture. 

Acid Potassium Carbonate, \ HKC0 3 , Saleratus, 
"Bicarbonate of Potash" is prepared by passing C0 2 
through a strong solution of potassium carbonate. 

Potassium Nitrate, KN0 3 , Nitrate of Potash, Salt- 
peter, Niter. — This salt is found as an efflorescence 
on the soil in tropical regions, especially in India. It 
is obtained thence by leaching. J It is formed arti- 

* Vast deposits of potassium salts have been opened up to us at the 
Stassfurth salt mines in G-ermany, the suppiy from which is more than 
from the wood-ash sources of the whole world. " Only about 13,000 tons 
of potash were sent to market from the United States and British America 
in 1870, and yet from Stassfurth, where a dozen years ago it was not sup- 
posed that a single ton could be produced, 30,000 tons of potassium chloride 
were manufactured and supplied to consumers upon both continents during 
the following year. The surface salts at these mines, which hold the 
potash, are practically inexhaustible, and millions of tons will be supplied 
in succeeding years"— Fireside Science. 

t The molecule of carbonic acid is H 2 C0 3 . In potassium carbonate, 
K 2 C0 3 , both the atoms of H contained in the carbonic acid are replaced by 
the metal K ; in hydrogen potassium carbonate, HKC0 3 , only one atom of 
H is thus replaced. 

X It was manufactured in the Mammoth Cave, Kentucky, during the 
war of 1812. The remains of the works, and even the deep ruts of the 
wagon-wheels, are still to be seen, preserved in the pure, still air. 



130 INORGANIC CHEMISTRY. 

ficially by piling up great heaps of mortar, refuse of 
sinks, stables, etc. "In about three years, these are 
washed, and each cubic foot of the mixture will fur- 
nish four or five ounces of saltpeter." It dissolves 
in about three and a half times its weight of cold 
H 2 0. 

Properties and Uses. — It is cooling and anti- 
septic ; hence it is used with common salt (NaCl) for 
preserving meat. It parts readily with its 0, of 
which it contains nearly 48 per cent., and defla- 
grates with charcoal brilliantly. Every government 
keeps a large supply on hand for making gunpow- 
der, in the event of war. Gunpowder is now com- 
posed of about six parts, by weight, of niter, and one 
each of charcoal and sulphur — the proportion vary- 
ing with the purpose for and the country in which 
it is made. Its explosive force is due to the expan- 
sive power of the gases formed. At the touch of a 
spark the saltpeter gives up its to burn the S and 
C. The reaction that ensues may be approximately 
represented as follows : 2KN0 3 + S + 3C = K 2 S + N 2 + 
3C0 2 . 

Besides N and C0 2 , smaller quantities of other 
gases are formed, which, with the sudden increase of 
temperature (to about 2,200°C), expand till they oc- 
cupy at least 1,500 times the space of the powder. 
The bad odor of burnt powder is due to the slow 
formation of H 2 S in the residuum. Fire-works are 
composed of gunpowder ground with additional C 
and S, and some coloring matter. Zinc filings pro- 
duce green stars ; steel filings, variegated ones. 



SODIUM. 131 

Sr2N0 3 tinges flame with crimson; Ba2N0 3 with 
green. Saks of copper give a blue, and camphor a 
pure white flame. 

Potassium Chlorate, KC10 3 , is a white, crystallized 
salt much used in preparing oxygen, making 
matches, fire-works, etc. It is a powerful oxidizing 
agent.* 

Potassium Bichromate, f K 2 Cr 2 7 , is a red salt 
highly valued in dyeing, calico-printing, and photo- 
lithography. If we mix a solution of this salt and 
one of sugar of lead, a yellow-colored precipitate will 
be formed, known in the arts as chrome-yellow (lead 
chromate). K 2 Cr 2 7 is a strong oxidizing agent, be- 
ing readily reduced in an acid solution to a salt of Cr. 



SODIUM. 

Symbol, Na Atonjic Weight, 23 Specific Gravity, 0,972, 

This metal is found principally in common salt. 
Its preparation is similar to that of K, but is more 

* Examples: 1. Put in a porcelain crucible as much KC10 3 as will lie on 
tlie point of a knife-blade, and half as much S. On grinding with the pes- 
tle, rapid detonations will ensue. 2. Place in a wine-glass five or six pieces 
of phosphorus as large as a grain of wheat, and cover with crystals of 
KCIO3. Pill the glass two thirds full of H 2 0. By means of a pipette, or a 
glass funnel, introduce into immediate contact with the KC10 3 a few drops 
of strong HoSO*. A violent chemical action will immediately occur, and 
the phosphorus will burn under the water with vivid flashes of light. 

t Chromic anhydride (Cr 2 3 ) is an oxide of chromium (chroma, color), a 
metal prized only for its numerous brilliantly colored compounds. It is 
rather rare, and mainly found in chrome iron-stone (PeO.Cr 2 3 ). 



132 INORGANIC CHEMISTRY. 

easily managed. It is very like K in appearance, 
properties, and reaction. It decomposes water ener- 
getically, but does not take fire like the K, unless 
the water is warm. The test of all the soda salts is 
the yellow tint which they give to flame. 

Compounds, — Sodium Chloride, NaCl, Common 
Salt, is a mineral substance absolutely necessary to 
the life of human beings and the higher orders of 
animals. It does not enter into the composition of 
tissue, but is essential to the proper digestion of the 
food, and to the removal of worn-out matter. (See 
" Physiology, " p. 137.) It is used extensively in the 
preservation of foods and in the manufacture of 
many substances. As salt is so universally necessary, 
it is found everywhere. Our Father in fitting up a 
home for us, did not forget to provide for all our 
wants. The quantity of salt in the ocean is said to 
be equal to five times the mass of the Alps. Salt 
lakes are scattered here and there ; saline springs 
abound; and besides these, in the earth are stored 
great mines, probably produced by the evaporation 
of salt lakes in some ancient period of the earth's 
history. Near Cracow, Poland, are the remarkable 
salt mines of Wieliczka, which have been quarried 
out of a bed calculated to be five hundred miles long, 
twenty miles wide, and nearly a quarter of a mile 
thick. In Spain, and lately in Idaho, it has been 
quarried out in perfect cubes, transparent as glass, 
so that a person can read through a large block. 

Preparation. — On the sea-shore it is manufactured 
by the evaporation of sea-water, each gallon contain- 



SODIUM. 133 

ing about four ounces.* At Syracuse, New York, 
near by and underneath the Onondaga Lake, is ap- 
parently a great basin of salt-water, separated from 
the fresh-water above by an impervious bed of clay. 
Upon boring through this, the saline water is 
pumped up in immense quantities. The H 2 is 
evaporated by heating in large iron kettles over a 
fire, or in shallow, wooden vats by exposure to the 

Fig. 57. 




Hopper form of salt crystals. 

sun — whence the name " solar salt." If boiled down 
rapidly, fine table-salt is made ; if more slowly, 
coarse salt, as large crystals have time to form. 
Frequently they assume a " hopper shape," one cube 
appearing, then others collecting at its edges, and 
gradually settling, until a hollow pyramid of salt- 
cubes, with its apex downward, is formed. 

* "Salt is soluble in less than three times its weight of H 2 0. It is 
scarcely more soluble in hot than cold H 2 0, and a saturated solution (one 
containing all it will dissolve) has about 36 per cent. Sea-water contains 
about 3 per cent. Sodium carbonate was formerly obtained from the ashes 
of sea-plants, as potassium carbonate is now from the ashes of land-plants." 
— Roscoe. 



134 INORGANIC CHEMISTRY. 

Uses. — NaCI is used largely in food, for preserv- 
ing meats and fish, and for preparing CI, HCI, and 
the various compounds of Na. 

Sodium Hydroxide, Caustic Soda, NaOH, is pre- 
pared from sodium carbonate by the action of milk 
of lime : 

Na 2 C0 3 + Ca(0H) 2 = CaC0 3 + 2Na0H. 

It resembles KOH, but is less powerful in its 
chemical action. It is largely used in soap-making, 
and other technical operations. 

Sodium Sulphate (Na 2 S0 4 , 10H 2 O), Glauber's Salt, 
named from its discoverer, is made in great quanti- 
ties from NaCI, as the first stage in the manufacture 
of sodium carbonate. It is remarkably efflorescent, 
the salt, by exposure to the air, losing its ten 
molecules of H 2 0.* It has a bitter, saline taste, and 
is used in medicine. 

Sodium Carbonate (Na 2 C0 3 , 10H 2 0), Sal-soda,, is 
used extensively in the arts. It is, therefore, of great 
importance to all consumers of soap, glass, etc., that 
it should be manufactured as cheaply as possible. 
Leblanc's process of making it from NaCI is the most 
important method. The operation comprises two 

* Experiment : Make a saturated solution of sodium sulphate in warm 
water, and with it fill a bottle. Stuff cotton loosely into the neck of the 
bottle, and let it stand. The salt will remain for months without crystal- 
lizing ; but if it be taken up, and shaken ever so little, the whole mass will 
instantly form into crystals, so filling the bottle that not a drop of water 
will escape, even if it be inverted. Should there be any hesitation in 
crystallizing at the moment, drop into the bottle a minute crystal of the 
salt, and the effect will instantly be seen in the darting of new crystals in 
every direction. 



SODIUM. 135 

stages: Changing, 1. NaCl into Na 2 S0 4 : and, 2. Na 2 S0 4 
into Na 2 C0 3 . 

1. A mixture of NaCl and H 2 S0 4 is heated. 
Na 2 S0 4 is formed with a copious evolution of HC1. 
The fumes of this gas are conducted into the bottom 
of a vertical flue filled with pieces of coke wet with 
constantly falling H 2 0. The gas is here absorbed, 
and a weak muriatic acid formed in great quantities.* 

2. The Na 2 S0 4 is heated with chalk (CaC0 3 ) and char- 
coal. The C deoxidizes the Na 2 S0 4 , changing it into 
Na 2 S. The metals of the Na 2 S and the CaC0 3 change 
places, forming Na 2 C0 3 and CaS. Out of this mass, 
called from its color "black-ash," the Na 2 C0 3 is dis- 
solved, f and then evaporated to dryness, making the 
"soda-ash" of commerce. 

Hydrogen Sodium Carbonate (HNaC0 3 ), " Bicar- 
bonate of Soda" is the "soda" of the kitchen. It is 
prepared by the action of C0 2 on sodium carbonate. 
The C0 2 may be easily liberated by the action of 
an acid. (See p. 244.) 

Sodium Nitrate, NaN0 3 , occurs in large deposits as 
Chili Saltpeter. It attracts moisture from the air, 
and so can not supersede KN0 3 in the manufacture 
of gunpowder. It is used in making nitric acid. 

* This acid was formerly allowed to escape, causing the destruction of 
all vegetation in the neighborhood. It is now, however, absorbed so per- 
fectly that the gases which escape from the top of the chimney will not 
render turbid a solution of silver nitrate (see page 97), showing that there 
is not a trace of the acid left. 

t The insoluble residuum of CaS, and the superfluous coal, form around 
the alkali works a mountain of waste. Attempts have been made to ex- 
tract the S, and at the Paris Exposition large blocks thus obtained were 
exhibited. 



136 INORGANIC CHEMISTRY. 

AMMONIUM. 

Symbol, NH 4 . 

This is a compound which has never been sep- 
arated, but it is generally thought to be the base of 
the salts formed by the action of the acids upon the 
alkali ammonia, which closely resemble the corre- 
sponding salts of K. The analogy between it and the 
simple metals is so very striking * that it is considered 
a compound metal, acting the part of a simple one, 
as Cy does that of a compound halogen (see p. 74). 
All attempts to separate this compound ammonium 
base from the ammonium salts result in NH 3 . 

Compounds. — Ammonium Chloride, NH 4 CI, Sal- 
ammoniac, is prepared from the ammoniacal liquor 
of the gas-works. (See p. 73.) It is obtained either 
as a fine crystalline meal, called "flowers of sal-ammo- 
niac " ; as a tough, fibrous, semi-transparent, crystal- 
line mass; or as a fine powder. In no form does it 
reveal any trace of the pungent ammonia, yet this 
can easily be set free, and as we have already seen 
(p. 35). Sal-ammoniac is soluble in H 2 0, and when 
dissolved in water causes a marked reduction in the 
temperature. It has neither color nor odor, but has 
a very saline taste. It is used in medicine, in the 
preparation of NH 3 and the salts of NH 4 , in dyeing, 

* When NH 3 is dissolved in H 2 0, forming NH 3 HOH the compound may- 
be represented as (1STII 4 ) OH. Comparing this with the formula for caustic 
potash, KOH, we see that the group of elements NH 4 corresponds to the 
EL. Thus we may call a solution of NH 4 , ammonium hydroxide or "caustic 
ammonia," as one of potash is a potassium hydroxide or "caustic potash." 
Both act as powerful bases, neutralize the acids and form soaps. 



AMMONIUM. 13 7 

and also in soldering, as it dissolves the coating of 
the oxide of the metal and preserves the surfaces 
clear for the action of the solder. It is also much 
used now in certain electric batteries. 

Ammonium Carbonate, Sal-volatile, Smelling Salts, 
is prepared by the action of chalk upon sal-ammo- 
niac. It is a sesquicarbonate, but by the constant 
loss of NH 3 it becomes crusted with a spongy coat 
of the " bicarbonate," hydrogen ammonium carbon- 
ate (NH 4 )HC0 3 . It is largely used by bakers in 
raising cake. (See p. 245). 

Ammonium Nitrate (NH 4 N0 3 ) may be readily 
formed by cautiously adding dilute HN0 3 to aqua 
ammonia until the liquid becomes neutral, and then 
evaporating. Long, needle-shaped crystals will form. 
Thus two fiery liquids combine to produce a solid 
having no resemblance to either of them. By heat 
this salt may be converted into H 2 and N 2 0. (See 
p. 32.) All the salts of ammonium are decom- 
posed by heat. 

THE RARE METALS OF THE ALKALIES. 

Lithium (Li), Rubidium (Rb), and Caesium (Cs) are 
much rarer than K and Na. Li is the lightest of all 
metals (specific gravity 0.59) and it has the lowest 
atomic weight (7). The metal and its salts resemble 
Na and its salts, while Rb and Cs are more like K. 
Cs was the first metal discovered by spectrum an- 
alysis. (See page 147.) 



138 



INORGANIC CHEMISTRY. 



METALS OF THE ALKALINE EARTHS. 

Ca, Ba, and Sr. 



CALCIUM. 



Symbol, Ca Atomic Weight, 40 Specific Gravity, 1.57. 

Ca exists abundantly in limestone, gypsum, and in 
the bones of the body.* It commonly occurs, in 
nature, as sulphate or carbonate ; and, in commerce, 
as oxide. 

Compounds. — Calcium Oxide (CaO), Caustic or 

Quicklime, is obtained by 
heating limestone (CaC0 3 ) 
in large kilns. The C0 2 is 
driven off by the heat, and 
the CaO is left as a white 
solid. 

Fig. 58 shows a form of 
lime-kiln in which the proc- 
ess is continuous. At a, 
6, c, are the doors for the 
fuel, ash-pit, etc. The kiln 
is fed at the top with lime- 
stone from time to time, 
while the lime, settling at 
the bottom, is taken out at / as fast as it is formed. 

* " There are 5 lbs. of phosphate of lime, one of carbonate of lime, and 
3 oz. of fluoride of calcium in the body of an adult weighing 154 lbs."— 
Nichols. 




CALCIUM. 139 

Properties. — CaO has such an affinity for H 2 0, that 
fifty-six pounds of lime will absorb eighteen pounds 
of H 2 0, forming Ca(0H) 2 , calcium hydroxide or 
"slaked lime," expanding to several times its original 
size, with the evolution of much heat. CaO absorbs 
H 2 from the air, and then C0 2 , and gradually crum- 
bles to a coarse powder, becoming " air-slaked lime." 
Hydraulic lime is made from limestone containing 
more than 10 per cent, of silica, and will harden 
under water. 

Calcium Hydroxide, Ca(0H) 2 , is slightly soluble in 
water, and its clear solution is called "lime-water." 
A film of calcium carbonate will soon form on the 
surface of lime-water when exposed to the air. Lime- 
water has an alkaline reaction, i. e., will turn red 
litmus blue, and acts as a mild alkali. 

Uses. — Whitewash is a "milk of lime," i.e., lime 
diffused through water. Concrete is a cement of 
coarse gravel and hydraulic lime. It is of great 
durability. Hard finish is a kind of plaster in which 
gypsum is used to make the wall smooth and hard. 
Calcimine is a variety of whitewash made of whiting 
or plaster of Paris. Mortar is a mixture of lime and 
sand wet with H 2 0. It hardens by absorbing C0 2 
from the air to form a carbonate, and partly, perhaps, 
by uniting with the Si0 2 of the sand to form a 
silicate.* 

* "If common mortar be protected from the air, it will remain without 
hardening for many years. It is stated that lime still in the condition of 
a hydrate has been found in the Pyramids of Egypt. When the ruins of 
the old castle of Landsberg were removed, a lime-pit, that must have been 
in existence three hundred years, was found in one of the vaults. The sur- 



140 INORGANIC CHEMISTRY. 

Lime is valuable as a fertilizer. It acts by rapidly 
decomposing all vegetable matter, and thus forming 
NH 3 for the use of plants.* It also sets free the 
alkalies that are combined in the soil, and furnishes 
them to the plants, becoming itself a carbonate. 
Lime is also used extensively in the preparation of 
bleaching powder, in refining sugar, in making can- 
dles, in tanning, and in the manufacture of coal-gas. 

Calcium Carbonate, CaC0 3 , includes limestone, 
chalk, marble, and marl, and forms the principal 
part of corals, shells, etc. H 2 charged with C0 2 dis- 
solves CaC0 3 , which, when the gas escapes on ex- 
posure to the air, is deposited. In limestone regions, 
the water trickling down into caverns has formed 
" stalactites," which depend from the ceiling, and 
" stalagmites," that rise from the floor. These fre- 
quently assume curious and grotesque forms, as in 
many limestone caves. Around many springs, the 
water, charged with CaC0 3 in solution, flows over 
moss or some vegetable substance, upon which the 
stone is deposited. The spongy rock thus formed is 
called calcareous tufa, or " petrified moss." (See 
"Geology," page 49.) Marble is crystalline limestone. 
Chalk or marl is a porous kind of limestone, formed 



face was carbonated to the depth of a few inches, but the lime below this 
was fresh as if just slaked, and was used in laying the foundations of the 
new building.' 1 — American Cyclopedia. 

* If applied to a compost heap, it will set free NH 3 , thus robbing it of 
its most valuable constituent. This can be saved by sprinkling the pile 
with dilute H 2 S0 4 , or plaster, or by mixing it with dry muck, which will 
absorb the gas. If there is any copperas (produced by the oxidation of iron 
pyrites) in the soil, the lime will decompose it, forming gypsum and iron- 
rust, thus changing a noxious ingredient into an element of fertility. 




141 



A care with stalactites and stalagmites. 

from beds of shells, but not compressed as in 
common limestone. Whiting is ground chalk. 

Calcium Sulphate, (CaS0 4 ,2H 2 0), Gypsum, Plaster, 
etc.* — This occurs as beautiful fibrous crystals in 
satin spar, as transparant plates in selenite, and as a 
snowy-white solid in alabaster. It is soft, and can be 
cut into rings, vases, etc. When heated it loses its 
water of crystallization, and is ground into powder, 
called "Plaster of Paris,' 1 from its abundance near 
that city. Made into a paste with H 2 0, it first swells 

* Comparing the formula H„S0 4 and CaSO*, we see that one atom of 
Ca can replace two atoms of H; it is therefore one of the class of atoms 
called "bivalent. 



142 INORGANIC CHEMISTRY. 

up, and then immediately hardens into a solid mass. 
This property fits it for use in copying medals and 
statues, forming molds, fastening metal tops on 
glass lamps, etc. Plaster (unburned or burned 
gypsum) is used as a fertilizer.* Its action is prob- 
ably somewhat like that of lime, and in addition it 
gathers up ammonia and holds it for the plant. 

Calcium Sulphite, CaS0 3 , should be distinguished 
from the sulphate. It is much used in preserving 
cider, being sold as " sulphite of lime." 

Calcium Phosphate, "Phosphate of Lime" is fre- 
quently termed hone phosphate, as it is a constituent 
of bones. (See p. 113.) It is found as a mineral in 
Florida, South Carolina,! and Canada. It is the valu- 
able part of certain guanos. Fertilizers are prepared 
by treating ground bones with H 2 S0 4 , forming the 
so-called superphosphate of lime,J a mixture of gyp- 
sum and hydrogen calcium phosphate. The latter 

* It is said that Franklin brought CaS0 4 into use by sowing it over a 
field of grain on the hill-side, so as to form, in gigantic letters, the sentence, 
"Effects of gypsum." The rapid growth produced soon brought out the 
words in bold relief, and decided the destiny of gypsum among farmers. 

t "Along the coast of South Carolina are millions of tons of rocks hold- 
ing this important element of plant-food. The phosphatic beds extend over 
an area of several hundred square miles, and in some cases they are twelve 
feet thick. It is estimated that from 500 to 1000 tons underlie each acre." 
—Fireside Science. 

X Ca 3 2P0 4 (tricalcium phosphate) +2H Q S0 4 =H 4 Ca2PO* (acid phosphate 
or superphosphate) + 2CaS0 4 (calcium sulphate). As the gypsum is only 
slightly soluble in water, the superphosphate may be removed from the 
mass by filtering, and used as a fertilizer, or to form phosphorus. In that 
case it is converted into calcium metaphosphate, Ca2P0 3 , by evaporating 
and heating the residue to redness, and then mixed with C and heated 
again in earthenware retorts. The following reaction takes place : 

3Ca2PO s + 10C=4P + Ca 3 2P0 4 + 10CO, 
being partly changed back into the original form, Ca 3 2P0 4 . 



STRONTIUM AND BARIUM. 143 

furnishes phosphorus to the growing plant to store 
in its seeds. — Example : corn, wheat. 

Calcium Hypochlorite (CaCl 2 2 ) is an ingredient 
of chloride of lime or "bleaching powder." This is 
prepared by passing a current of CI over pans of 
freshly slaked lime. It is much used in bleaching 
and as a disinfectant. 

Calcium Chloride, the other compound of bleach- 
ing powder, was made in preparing C0 2 (see p. 63). 
It is used by chemists for drying gases. It absorbs 
H 2 so greedily that in the open air it will soon 
dissolve. 



STRONTIUM AND BARIUM. 

These metals are very like Ca. The salts of Ba 
give a green tint to a flame and those of Sr a beauti- 
ful crimson ; and are hence much used in pyrotechny. 
Barium sulphate, commonly called barytes, is found 
as a white mineral, noted for its weight, whence it 
is often termed heavy spar. Indeed, the term barium 
is derived from a Greek word meaning heavy. This 
mineral is largely used for adulterating white-lead. 
BaCl 2 is a test for H 2 S0 4 . (See p. 106.) 

Strontium occurs as celestite, SrS0 4 , and as stron- 
tianite, SrC0 3 . Its most important compounds are : 
the hydroxide, Sr(0H) 2 , which is used in sugar- 
making to extract the sugar from molasses ; and 
the nitrate, Sr2N0 3 , which is used as a constituent 
of "red fire." The metals themselves are prepared 
with difficulty, and are of no practical importance. 



144 INORGANIC CHEMISTRY. 

M AGN E S I U M.* 

Symbol, % . . , . Atonjic Weight, 24,3 , , . , Specific Gravity, ij. 

Source. — Mg is found in augite, hornblende, meer- 
schaum, soap-stone, talc, serpentine, dolomite, and 
other rocks. Its salts give the bitter taste to sea- 
water. When pure, it has a silvery luster and 
appearance. It is very light and flexible. A thin 
ribbon of the metal will take fire from an ignited 
match, and burns with a white cloud of MgO, pro- 
ducing such a brilliant light that an ordinary flame 
casts dense shadows. This light possesses such 
actinic or chemical properties, that it is used for 
taking photographs at night, views of coal mines, 
interiors of dark churches, etc. It has every ray of 
the spectrum, and so does not, like gas-light, change 
some of the colors of an object upon which it falls. 
Magnesium lanterns are occasionally used for purposes 
of illumination. By means of clockwork, the metal, 
in the form of a narrow ribbon, is fed in front of a 
concave mirror, at the focus of which it burns. Mg 
is prepared from its chloride, MgCl 2 , by electrolysis, 
or by reduction by means of Na. It is hoped that 
the process of manufacture may be cheapened, so 
that Mg may be brought within the scope of the 
arts. 

* With. Mg are classed Zn, Cd, and G-l. Mg is treated here for con- 
venience, while Zn is described among the useful metals. Cd is used in 
making some alloys and its salts are employed to some extent in photog- 
raphy and medicine. G-l occurs in beryl and emerald. It is of no practical 
importance. 



ALUMINIUM. 145 

Compounds. — " Magnesia alba" the common mag- 
nesia of the druggist,* is a basic magnesium car- 
bonate. Magnesium sulphate (MgS0 4 ,7H 2 0) is known 
as Epsom salt, from a celebrated spring in England 
in which it abounds. 



A L U M I N I U M.f 

Symbol, Al Atomic Weight, 27 Specific Gravity, 2.G. 

Source. — Al is named from alum, in which it 
occurs. It is also called the "clay metal." It is the 
metallic base of clay, mica, slate, and feldspar rocks. 
Next to '0 and Si, it is probably the most abundant 
element of the earth's crust. It is a bright, silver- 
white metal ; does not oxidize in the air, nor tarnish 
by H 2 S. It gives a clear musical ring; is only one 
fourth as heavy as Ag ; is ductile, malleable, and 
tenacious. It readily dissolves in HC1, and in solu- 
tions of the alkalies, but with difficulty in HN0 3 and 
H 2 S0 4 . On account of its abundance (every clay- 
bank is a mine of it) and useful properties, it must 
ultimately come into common use in the arts and 
domestic life. 

Compounds. — Aluminium Oxide (Al 2 3 ). — Alumina 
crystallized in nature, forms valuable gems. They 

* The magnesia of commerce is made by mixing hot solutions of 
magnesium sulphate and sodium carbonate. It contains a varying pro- 
portion of magnesium hydrate. Dolomite, a rock composed of magnesium 
carbonate and calcium carbonate, makes a hydraulic cement that "sets" 
under water.— (" Geology," p. 51.) 

t Quite a number of rare metals (G-a, In, Sc, etc.) are classed with Al, but 
none of them are of sufficient interest to be treated in an elementary work. 



146 



INOEGANIC CHEMISTRY. 



are variously colored by impurities; — blue, in the 
sapphire ; green, in the Oriental emerald ; yellow, in 
the Oriental topaz ; red, in the ruby. Massive, impure 
alumina is called emery, and used for polishing. 

Aluminium Silicate, Silicate of Alumina, Com- 
mon Clay. — "When rocks decay by the resist- 
less and constant action of the air, rain, and 
frost, they crumble into soil. This contains clay, 
silica, and also lime, magnesia, oxide of iron, etc. 
The clay gives firmness to the soil and retains 
moisture, but is cold and tardy in producing vege- 
table growth. When free from Fe, it is used for 
making tobacco-pipes. When colored by ferric oxide, 
it is known as ocher, and is employed in painting. 
Common stone and red earthen-ware are made from 
coarse varieties of clay; porcelain and china-ware 
require the purest material. Fire-bricks and crucibles 

are made from a clay which 
contains much Si0 2 . Fullers' 
earth is a very porous kind, and 
by imbibition absorbs grease and 
oil from cloth. 

Glazing. — When any article of 
earthen-ware has been molded 
from clay, it is baked. As the 
ware is porous, and will not hold 
H 2 0, a mixture of the coarse ma- 
terials from which glass is made 
is then spread over the vessel, 
and heated till it melts and forms 
a glazing upon the clay. Ordinary stone-ware is glazed 



Pig. 60. 




Baking Porcelain. 



ALUMINIUM. 147 

by simply throwing damp NaCl into the furnace. This 
volatilizes, and being decomposed by the hot clay 
makes a sodium silicate over the surface, while fumes 
of HC1 escape. Pb is sometimes used to give a yellow- 
ish glaze, which is very injurious, as it will dissolve 
in vinegar, and form sugar of lead, a deadly poison. 
The color of pottery-ware and brick is due to the 
oxide of iron present in the clay. Some varieties 
have no iron, and so form white ware and brick. 

Alum is made by treating clay with H 2 S0 4 , form- 
ing an aluminium sulphate. On adding potassium 
sulphate a double salt is produced, which separates in 
beautiful octahedral crystals (A1 2 3S0 4 ,K 2 S0 4 + 24H 2 0). 
Instead of the potassium salt, an ammonium salt* 
is now generally added, and an ammonium alum 
made, which takes the place of the former in the 
market.f Alum is much used in dyeing. It unites 
with the coloring matter, and binds it to the fibers 
of the cloth. It is therefore called a mordant (mor- 
deo, I bite). 



SPECTRUM ANALYSIS. 

Some of the metals named as rare have been 
recently discovered by what is termed Spectrum 
Analysis. We have already noticed that various 

* Ammonium sulphate, from the ammoniacal liquor of the gas-works. 
(See page 73.) 

t There are a large number of other alums known, in which iron, 
chromium, and manganese are substituted for the aluminium in common 
alum ; all these alums occur in regular octahedra, and can not be separated 
by crystallization when present in solution together. 



148 INORGANIC CHEMISTRY. 

metals impart a peculiar color to flame ; thus Na 
gives a yellow tinge ; Cu, a green, etc. If now we 
look at these colored flames through a prism, we 
shall find, instead of the " spectrum" we are familiar 
with, a dark space strangely ornamented with bright- 
tinted lines. Thus the spectrum of Na has one 
double, yellow line ; * K, a violet and a red line ; Cs, 
two beautiful blue lines. Each metal makes a dis- 
tinctive spectrum, even when the flame is colored by 
several substances at once. This method of analysis 
is so delicate that ts o, 000,0 00- of a grain of Na, or 
6,000,0 00 of Li, can be detected in the flame of an 
alcohol lamp ; f while a substance exposed to the air 
for a moment even will give the Na lines from the 
dust it gathers. Li has thus been found to exist in 
tea, tobacco, milk, and blood, although in such 
minute quantities as to have eluded detection by 
former methods of analysis. 



PRACTICAL QUESTIONS. 

1. In the experiment with Na Q S0 4 on page 134, an accurate ther- 
mometer will show that in making the solution, the temperature of the 
liquid will fall, and in its solidification, will rise. Explain. 

2. If, in making the solution of ]STa 2 S0 4 , we use the salt which has 
effloresced, and so become anhydrous, the temperature will rise instead of 
falling as before. Explain. 

3. "Why is KN0 3 used instead of NalSTOa for making gunpowder? 

4. Why is a potassium salt preferable to a sodium one in glass-making? 

* The yellow, sodium line consists of two lines lying so closely together 
as to seem as one. They correspond to Eraunhofer's lines D, as given in 
the drawings of Kirchhoff and Bunsen. 

t Eor the more perfect examination of the spectra, a " spectroscope " is 
used. This consists of a tube with a narrow slit at one end, which lets 
only a narrow beam of light fall upon the prism within, and at the other 
a small telescope, through which one can look in upon the prism and ex- 
amine the spectrum of any flame. (See "Astronomy," p. 285.) 



PRACTICAL QUESTIONS. 149 

5. What is the glassy slag so plentiful about a furnace? 

G. State the formulas of niter, saleratus, carbonate and bicarbonate of 
soda, plaster, pearlash, saltpeter, plaster of Paris, gypsum, carbonate and 
bicarbonate of potash, sal-soda, and soda. 

7. Explain how ammonium carbonate is formed in the process of 
making coal-gas. 

8. Upon what fact depends the formation of stalactites? 

9. Why is HE kept in gutta-percha bottles? 

10. Explain the use of borax in washing. 

11. How are petrifactions formed? 

12. In what part of the body, and in what forms, is phosphorus found? 
13 "Why are matches poisonous? What is the antidote? (See "Physiol- 
ogy," Page 209.) 

14. Will the burning phosphorus ignite the wood of the match? 

15. What principle is illustrated in the ignition of a match by 
friction ? 

16. How much H 2 would be required to dissolve a pound of KN0 3 ? 

17. What causes the bad odor after the discharge of a gun? 

18. Write in parallel columns (see Question 41, page 85), the properties 
of common and of red phosphorus. 

19. What causes the difference between fine and coarse salt? 

20. Why do the figures in a glass paper-weight look larger when seen 
from the top than from the bottom ? 

21. What is the difference between water-slaked and air-slaked lime? 

22. Why do oyster-shells on the grate of a coal-stove prevent the forma- 
tion of clinkers? 

23. How is lime-water made from oyster-shells? 

24. Why do newly -plastered walls remain damp so long? 

25. Will lime lose its beneficial effect upon a soil after frequent applica- 
tions ? 

26. What causes plaster of Paris to harden again after being moist- 
ened? 

27. What is the difference between sulphate and sulphite of lime? 

28. What two classes of rays are contained in the magnesium light? 

29. What rare metals would become useful in the arts, if the process of 
manufacture were cheapened? 

30. Why is lime placed in the bottom of a leach-tub ? 

31. Is saleratus a salt of K or of Na? 

32. Why will ISTa burst into a blaze when thrown on hot water? 

33. Why are certain kinds of brick white ? 

34. Illustrate the power of chemical affinity. 

35. Why does not a candle lowered into a jar of CI go on burning in- 
definitely ? 



150 



iJsroEGAisric chemistry. 



THE HEAVY METALS, 



IRON. 

Synjbol, Fe. . . . ^tonjic Weight, 56 ... . Specific Gravity, 7.8. 

Iron is the symbol of civilization. Its value in 
the arts can be measured only by the progress of 
the present age. In its adaptations and employ- 
ments, it has kept pace with scientific discoveries 
and improvements, so that the uses of iron may 
readily indicate the advancement of a nation. It is 
worth more to the world than all the other metals 
combined. We could dispense with gold and silver — 
they largely minister to luxury and refinement — but 
iron represents solely the results of honest labor. Its 
use is universal,* and it is fitted alike for massive 
iron cables, and for screws so tiny that they can be 
seen only by the microscope, appearing to the naked 
eye like grains of black sand. 



* " Iron vessels cross the ocean, 
Iron engines give them motion, 
Iron needles northward veering, 
Iron tillers vessels steering, 
Iron pipe our gas delivers, 
Iron bridges span our rivers, 
Iron pens are used for writing, 
Iron ink our thoughts inditing, 
Iron stoves for cooking victuals, 
Iron ovens, pots, and kettles, 
Iron horses draw our loads, 
Iron rails compose our roads, 



Iron anchors hold in sands, 

Iron bolts and rods and bands, 

Iron houses, iron malls, 

Iron cannon, iron balls, 

Iron axes, knives, and chains, 

Iron augers, saws, and planes, 

Iron globules in our blood, 

Iron particles in food, 

Iron lightning-rods on spires, 

Iron telegraphic wires, 

Iron hammers, nails, and screws, 

Iron every thing we use." 



IRON. 151 

There is no " California ?1 of iron. Each nation 
has its own supply. No other material is so en- 
hanced in value by labor. 

1 lb. good iron is worth, say $ .04 

1 " bar steel -17 

1 " inch-screws 1.00 

1 " steel wire. 3 to 7.00 

1 " sewing-needles. .. 14.00 

1 " fish-hooks 20 to 50.00 

1 M jewel-screws for watches 3,500.00 

1 " hair-springs for American watches 16,000.00* 

Source. — Fe is rarely found native, i. e., in the 
metallic condition. Meteors, however, containing as 
high as 93 per cent, of Fe associated with Ni and 
other metals, have fallen to the earth from space. 
Fe in combination with various other substances is 
widely diffused. It is found in the ashes of plants 
and the bloodf of animals. Many minerals con- 
tain it in considerable quantities. The ores from 
which it is extracted are generally oxides or car- 
bonates. 

Preparation. — Smelting of Iron Ores. — Fe is locked 
up with in an apparently useless stone. C is the 
key that is ready made and left for our use by the 
Creator. The process adopted at the mines is very 
simple. A tall blast-furnace is constructed of stone 
and lined with fire-brick. At the top is the door, 

* One pound (Troy) of fine gold is worth in standard coin $248,062. All 
the above statements are based on careful and actual valuation. 

+ There are only about 100 grains of Fe in the blood of a full-grown 
person— about enough to make a ten-penny nail— yet it gives energy and 
life to the system. The metal is often administered as a tonic in the form 
of citrate or other salt of iron, and is a valuable medicine. 



152 



INORGANIC CHEMISTRY. 



and at the bottom are pipes for forcing in hot air, 
sometimes twelve thousand cubic feet per minute, 
by means of blowers driven by steam-power. The 



Fig. 61. 




A Blast-Furnace . 



furnace, after a fire has been started, is filled with 
limestone, coal (charcoal or coke), and iron ore, in 
alternate layers. The C* unites with the of the 
ore, and goes off as CO and C0 2 . The CaC0 3 forms 



* A little N sometimes unites with some C and K, forming potassium 
cyanide, or with Ti, if any is present, making beautiful copper-colored 
crystals of titanium cyano-nitride, which are hard enough to scratch 
glass. 



IRON. 153 

with the Si0 2 and other impurities a richly-colored 
glassy slag. The iron, as it is reduced, sinks in the 
molten state to the lowest part of the furnace (the 
crucible), covered with a layer of slag. The slag 
runs out in a constant stream from an opening at 
the proper height, while the iron is drawn off from 
time to time and run into channels formed in sand. 
The large main one is called the sow ; the smaller 
lateral ones are termed the pigs — hence the name 
pig-iron. 

Varieties of Iron. — The usual forms are cast, 
wrought, and steel, depending upon the proportion 
of C which they contain. Steel contains more C 
than wrought iron, and less than cast. The highest 
proportion of C in cast iron is about 6 per cent., 
while wrought iron contains only from 0.1 — 0.7 per 
cent. 

1. Cast Iron is the form which comes from the 
furnace. It is brittle, can not be welded, and is 
neither malleable nor ductile. It is well adapted for 
castings, since at the instant of solidification it ex- 
pands, so as to copy exactly every line of the mold 
into which it is poured. The castings may be made 
so soft as to be easily turned and filed, or so hard, 
by cooling in iron molds,* that no tool will affect 
them. 

2. Wrought or Malleable Iron is made by burn- 
ing the C from cast iron, in a current of highly-heated 
air, in what is called a reverberatory furnace. The 

* These molds are called " chills," and the iron is termed chilled iron. 
It is used for burglar-proof safes. 



154 



INORGANIC CHEMISTRY. 



Fig. 62. 




A Reverberatory Furnace, 



iron is stirred constantly, and exposed to the heated 
air by means of long " puddling-sticks," as they are 

termed. It is taken out while 
white-hot, and beaten under 
a trip-hammer to force out 
the slag ; and lastly, pressed 
between grooved rollers to 
bring the particles of Fe 
nearer each other and give 
it a fibrous structure.* It 
is now malleable and duc- 
tile, f much softer than cast iron, and can be welded. 
3. Steel contains less C than cast, and more than 
wrought, iron. It is therefore made from the former 
by burning out a part of the C, and from the latter 
by heating in boxes of charcoal, and so adding C.J 
The value of steel depends largely upon its temper. 
This is determined by heating the article, and then 
allowing it to cool. The higher the temperature the 
softer the steel. The workman decides this by 
watching the color of the oxide which forms on the 



* This fibrous structure is so noticeable that if a bar of the best Fe be 
notched with a chisel and then broken by a steady pressure, the fracture 
will present a stringy appearance, like that of a green stick. By constant 
jarring, however, Fe tends to take a crystalline structure, becoming rotten 
and brittle, so that cannon, the axles of cars, etc., are condemned after a 
certain time, although no flaw may appear. 

t It has been beaten into leaves so thin that they have been used for 
writing-paper— six hundred leaves being only half an inch in thickness— 
and has been drawn into wire as fine as a hair. 

X This is termed case-hardening. Cheap knives made of soft iron are 
often covered with a superficial coating of steel in this way. When we 
use such knives, we soon wear through this crust, and find metal beneath 
which will take no edge. 



IRON. 155 

surface.* Razors require a straw yellow ; table- 
knives, a purple ; springs and swords, a bright blue ; 
and saws, a dark blue tint.t 

Bessemer's Process is now extensively used for 
making steel. Several tons of the best pig-iron are 
melted, and poured into a large crucible hung on 
pivots so as to be easily tilted. Hot air driven in 
from beneath bubbles up through the liquid mass, 
producing an intense combustion. The roar of the 
blast, the hot, white flakes of slag ever and anon 
whirled upward, the long flame streaming out at the 
top, variegated by tints of different metals, and full of 
sparks of scintillating iron, all show the play of tre- 
mendous chemical forces. The operation lasts about 
twenty minutes, when the Fe is purified of its C and 
Si. Enough spiegel-eisen (looking-glass iron), from 
an ore rich in C and Mn, is added to convert it into 
steel, when it is poured out and cast into ingots. J 

* The thin pellicles of iron-rust on standing H O produce a beautiful 
iridescent appearance in the same way, the color changing with the thick- 
ness of the oxide. Just so a soap-bubble exhibits a play of variegated 
colors according to the thickness of the film in different parts. (See ''In- 
terference of Light," in "Physics.") 

t These colors are removed in the subsequent processes of grinding and 
polishing, but they may be seen in a handful of old watch-springs, to be 
obtained of any jeweler. 

t In 1760, there lived at Attercliffe, near Sheffield, a watch-maker 
named Huntsman. He became dissatisfied with the watch-springs in use, 
and set himself to the task of making them homogeneous. " If," thought 
he, "I can melt a piece of steel and cast it into an ingot, its composition 
should be the same throughout." He succeeded. His steel became famous, 
and Huntsman's ingots were in universal demand. He did not call them 
cast steel. That was his secret. The process was wrapped in mystery by 
every means. The most faithful men were hired. The work was divided, 
large wages paid, and stringent oaths taken. One midwinter night, as the 
tall chimneys of the Attercliffe steel-works belched forth their smoke, a be- 
lated traveler knocked at the gate. It was bitter cold ; the snow fell fast ; 



156 isroKGAsric chemistry. 

Pure Iron. — All varieties of cast iron, wrought 
iron, and steel, are more or less impure forms of Fe. 
The pure metal is little known, but can be prepared 
from its pure salts by reduction or electrolysis. 

Compounds. — 1. Black or Magnetic Oxide (Fe 3 4 ) 
is found in the loadstone, magnetic iron ore, scales 
which fly off in forging iron, and in mines in 
various parts of the United States. It is the richest 
of the ores, and contains as high as 72 per cent, of 
the metal. 2. Red Oxide of Iron, sesquioxide (ferric 
oxide, Fe 2 3 ), is seen in red iron ore, in the beau- 
tiful radiated and fibrous specimens of hematite,* 
specular f iron, red ocher, chalk, bricks and pottery- 
ware. The sesquioxide, combining with H 2 0, forms — 
3. Hydrated Sesquioxide of Iron (ferric hydroxide, 
Fe(OH) 3 ). This has a brown or yellow color, which 
changes to red by heat when the water is expelled, 
as in the burning of brick, pottery-ware,£ etc. These 



and the wind howled across the moor. The stranger, apparently a common 
farm-laborer seeking shelter from the storm, awakened no suspicion. The 
foreman, scanning him closely, at last granted his request, and let him in. 
Feigning to be worn out with cold and fatigue, the poor fellow sank upon 
the floor, and was soon seemingly fast asleep. That, however, was far from 
his intention. Through cautiously opened eyes, he caught glimpses of the 
mysterious process. He saw workmen cut bars of steel into bits, place them 
in crucibles, which were then thrust into the furnaces. The fires were 
urged to their utmost intensity until the steel melted. The workmen, 
clothed in rags, wet to protect them from the tremendous heat, drew forth 
the glowing crucibles, and poured their contents into molds. Hunts- 
man's factory had nothing more to disclose. The secret of cast steel was 
stolen. 

* Hcematites, blood-like, from the red color of its powder. 

t Speculum, a mirror, from the brilliant luster of its steel-gray crystals 
and mica-like scales in micaceous iron ore. 

$ Clay, containing ferrous oxide (ITeO), becomes red by its conversion 
into ferric oxide. 



IRON. 157 

oxides generally give the brown, yellow, or red tints 
seen in sand, gravel, etc. The ferric oxide and hy- 
drate are remarkable for the facility with which 
they absorb from the air, and impart it to other 
bodies. This is familiar in the rusting of nails in 
clapboards, hinges in gate-posts, hooks in ropes, 
etc., etc. 

Iron Carbonate, FeC0 3 , is found as spathic* and 
clay iron-stone, and often contains some manganese,! 
which fits it for the manufacture of certain kinds of 
steel, whence it is termed steel ore. In chalybeate 
springs, the free C0 2 in the water holds the FeC0 3 
in solution. On coming to the air, the C0 2 escapes, 
and the Fe, absorbing 0, is deposited as hydrated 
ferric oxide, forming the ochry deposit so common 
around such springs. 

Iron Disulphide (FeS 2 ), Iron Pyrites, FooVs Gold — 
so called, because it is often mistaken by ignorant 
persons for Au. It occurs in cubical crystals and 
bright shiny scales. It can be easily tested by roast- 
ing on a hot shovel, when we shall catch the well- 

* Spath, spar, as some specimens consist of transparent, shiny crystals, 
having the same form as calcareous spar (calcium carbonate). 

t Manganese is a hard, brittle metal, resembling cast iron in its color 
and texture. It takes a beautiful polish. Its binoxide, the black oxide of 
manganese, is used in the manufacture of O, CI, etc. By fusing Mn0 2 , 
KC10 3 , and KOH, a dark, green mass is obtained called "chameleon mineral." 
It contains potassium manganate. If a piece of this be placed in HoO, the 
solution will undergo a beautiful change from green, through various 
shades, to purple. This is owing to the gradual formation of permanganic 
acid. The change may be produced instantaneously by a drop of HoS0 4 . 
Potassium permanganate is remarkable for the facility with which it 
parts with its O, and thereby loses its color. It is used extensively as 
a disinfectant, and as a test of the presence of organic matter. (See 
page 48.) 



158 



INORGANIC CHEMISTRY. 



known odor of the S0 2 . FeS 2 is used as a source of 
S, and is roasted to furnish S0 2 in the manufacture 
of H 2 S0 4 . 

Ferrous Sulphate (FeS0 4 ,7H 2 0), Green Vitriol, 
Copperas, is made by the action of H 2 S0 4 on Fe, and, 
at Stafford, Connecticut, and other places, from FeS 2 , 
by exposure to air and moisture. It is used in dyeing, 
making ink, and in photography. 



Fig. 63. 



ZINC. 

Symbol, Zn . . . ♦ Atonjic Weight, 65,3 , , , , Specific Gravity, 6,9, 
Fusing Point, 811° F. or 433° C, 

Source. — Zn is found as ZnO, or red oxide, in New 
Jersey, and as ZnS, or zinc blende, in many places. 

Preparation. — ZnO* is smelted 
on the same principle as iron ore, 
by heating with C. The reaction 
is as follows : ZnO + C = Zn + CO. 

The Zn distils from the crucible 
a and is collected in the receiver 
d while the CO escapes. 

Properties. — Zn is ordinarily 
brittle, but when heated to 200° 
or 300° F., it becomes malleable, 
and can be rolled out into the 
sheet Zn in common use. At about 
400° F. it is so brittle that it can be powdered in a 




Beduction of Zinc Ore. 



* ZnS is roasted to convert it into ZnO. 



zinc. 159 

mortar. It burns in the air with a magnificent bluish 
light, forming flakes of ZnO, formerly called " Phi- 
losopher's Wool." "When exposed to the air Zn soon 
oxidizes, and the thin film of oxide formed over the 
surface protects it from further change. 

Uses. — Its economic uses are familiar. Sheet iron 
coated with Zn by being dipped in melted Zn forms 
what is termed galvanized iron. Water-pipes lined 
in this way with Zn are as unsafe as lead (see p. 162) 
until the Zn is entirely corroded. The oxide and 
carbonate of zinc are rapidly formed, and these 
poisonous salts remain in the H 2 0. There is the 
same objection to metallic-lined ice-pitchers. Gal- 
vanic action between the metals promotes corrosion. 
H 2 standing in reservoirs lined with Zn should not 
be used for drinking purposes. In the case of zinc- 
covered roofs the rain-water contains zinc* 

Compounds. — Zinc Oxide, ZnO, is sold as zinc- 
white, and is valued as a paint, since it does not 
blacken by H 2 S like white-lead, and is not hurtful 
to the painter. 

Zinc Chloride, ZnCl 2 , is used as a soldering fluid, 
which the plumbers prepare by " killing" muriatic 
acid with Zn. It is also used as a disinfectant and 
for a number of technical purposes. 

Zinc Sulphate, ZnS0 4 ,7H 2 0, White Vitriol, is used 
as a " dryer" in oil paints and varnishes. It is de- 
composed, when strongly heated, into ZnO, S0 2 , and 0. 

* When they were first introduced in Boston the washer- women com- 
plained that the rain-water was hard, decomposed the soap, and made their 
hands crack. 



160 IJSTOKGANIC CHEMISTRY. 



T I N« 



Symbol, Sn . . . . Atomic Weight, 119 ... . Specific Gravity, 7.3. 
Fusing Point, 446° F. or 230° C. 

Source. — Sn, though one of the metals longest 
known to man, is found in but few localities. It is 
reduced from its dioxide by the action of C. 

Properties. — It is soft and not very ductile, but is 
quite malleable, so that tin-foil is not more than T¥ Vo 
of an inch in thickness. When quickly bent, a bar of 
Sn emits a shrill sound, called the "tin cry," caused 
by the crystals moving upon each other. Sn does not 
oxidize at ordinary temperatures. Its tendency to 
crystallize is remarkable.* 

Uses. — Common sheet-tin is formed by dipping 
sheet-iron in melted Sn, which produces an artificial 
coating of the latter metal. If we leave H 2 in a tin 
dish, the yellow spots soon betray the presence of Fe. 
Pins are made of brass wire, upon which a bright 
white coating of tin is deposited, f Tin is a constit- 
uent of a number of important alloys (see p. 177). 
It forms two classes of salts : the stannous, in which 
it is bivalent, and the stannic, in which it is quad- 
rivalent. E. g., SnCl 2 and SnCl 4 . 

* Example: Heat a piece of tin till the coating begins to melt; then 
cool quickly in H 2 and clean in dilute aqua regia. The surface will be 
found covered with beautiful crystals of the metal. 

+ The pins are stuck in papers, as we see them, by machinery which 
picks them up out of a miscellaneous pile and inserts them in regular rows 
in the paper, ready for the market. The first part of the process is per- 
formed by a sort of coarse comb, which is thrust into the heap, and gathers 
up a pin in each of the spaces between the teeth. 



COPPER. 161 



COPPER. 

Synjbol, Cu, , ♦ , Atonjic Weight, 63,6 , . . . Specific Gravity, 8,9, 
Fusing Point, about 2012° F. or 1100° C. 

Source. — Cu is found native near Lake Superior, 
frequently in masses of great size. In these mines 
stone hammers have been discovered, the tools of a 
people older than the Indians, who probably occupied 
this continent, and worked the mines. In the western 
mounds, also, copper instruments are found. The 
sulphide, copper pyrites, is a well-known ore. Mai- 
achite (CuC0 3 ,Cu[OH] 2 ), the green carbonate, admits 
of a high polish, and is made into ornaments of ex- 
quisite beauty. 

Properties. — Cu is ductile, malleable, and an ex- 
cellent conductor of heat and electricity.* Its vapor 
gives a characteristic and beautiful green color to 
flame. HN0 3 is the solvent of Cu. Its test is NH 4 0H, 
forming in a solution a blue precipitate, which dis- 
solves in an excess of the re-agent with an intense 
dark blue color. 

Compounds. — Copper Acetate, Verdigris^ is pro- 
duced when we soak pickles in brass or copper 
kettles ; the green color which results is caused by 
this salt — a deadly poison. Preserved fruits, etc., 
should never stand in such vessels, as the vegetable 
acids dissolve Cu readily. r 

* Commercial Cu is never quite pure. Its properties are affected very 
markedly by the presence of even minute amounts of foreign substances. 

t The term verdigris is sometimes incorrectly applied to the green coat- 
ing of carbonate, which gathers upon brass or copper in a damp atmosphere. 



162 INORGANIC CHEMISTRY. 

Copper Oxide, CuO, is the black coating which 
is formed on copper or brass kettles. Such utensils 
should therefore be used only when perfectly bright, 
and never with fruits, sweetmeats, jellies, pickles, 
etc. 

Copper Sulphate (CuS0 4 ,5H 2 0), Blue Vitriol, is 
much used in dyeing, calico printing, and in voltaic 
batteries. 



LEAD. 



Symbol, Pb . . . . Atomic Weight, 207 Specific Gravity, 11,36. 

Fusing Point, 635° F, or 335° C. 

Source. — The most common ore of Pb is galena, 
PbS, which is reduced by processes which differ ac- 
cording to the purity of the ore. 

Properties. — Pb is malleable ; but contracts as it 
solidifies, so it can not be used for castings. Lead 
itself is not poisonous, and " bullets have been 
swallowed, and then thrown off without any harm 
except the fright." The soluble salts of Pb are, how- 
ever, all very poisonous. The effects seem to ac- 
cumulate in the system, and finally to manifest 
themselves in disease. Persons who work in lead 
compounds, as painters, after a time suffer with 
colics, paralysis, etc., while plumbers, who handle 
only metallic Pb, do not suffer. 

Uses. — Pb is much used for water-pipes, and is 
the most convenient of any metal for that purpose. 
Pure H 2 passing through the pipe will not corrode 
the Pb, but the of the air it contains forms an 



LEAD. 163 

oxide of lead which dissolves in the H 2 0, leaving a 
fresh surface for oxidation. If there are any sul- 
phates or carbonates in the H 2 0, they will form a 
coating over the Pb, and protect *it from further 
corrosion ; and as carbonate of lime is common in 
hard water, that is generally safe. If, when we 
examine a lead pipe that is in constant use, we find 
it covered with a white film, it is a good sign ; but 
if it is bright, there is cause for alarm. Still, how- 
ever much may be said about the danger, people will 
use lead pipes, and the following precautions should 
be observed : Before using the tvater in the morning, 
always let it run long enough to remove all ivhich has 
remained in the tvater-pipes during the night; and 
when the H 2 is let on again after it has been shut 
off for awhile, leave the faucet open until the pipe 
is thoroughly washed. 

The Test of Pb is H 2 S, forming lead sulphide, 
PbS. The following is an interesting illustration : 
Thicken a solution of lead acetate with a little gum- 
arabic, so as not to flow too readily from the pen, 
and then make any sketch which your fancy may 
suggest. This, when dry, will be invisible. When 
it is to be used, dampen the paper slightly on the 
wrong side, and then direct against it a jet of H 2 S. 
The picture will at once blacken into distinctness.* 

Compounds. — Lead Oxide, PbO, the well-known 
litharge, is formed by heating Pb in a current of 

* A delicate test for the presence of lead in water is this : Add a few 
drops of acetic acid and then a small pinch of powdered bichromate of 
potassium (K 2 0r 2 O 7 ). If Pb is present, a yellow turbidity will appear. 



164 



INORGANIC CHEMISTRT, 



Fig. 64. 




air.* Lead Dioxide, Pb0 2 , is formed by oxidizing 
PbO. A mixture of the two, called redr-lead, is used 
for coloring red sealing-wax, and as a paint. 

Lead Carbonate (PbC0 3 ), White-Lead, consists 
of basic lead carbonates, and is made as follows : 
Thousands of earthen pots fitted with 
covers and containing weak vinegar 
(acetic acid) and a small roll of Pb, are 
arranged in piles, and then covered 
with tan-bark. The acetic acid com- 
bines with the Pb, but the C0 2 formed 
by the decomposing tan-bark creeps in 
under the cover, driving off the acetic 
acid, and forming lead carbonate. The 
acetic acid, thus dispossessed, attacks 
another portion of the Pb, but is robbed 
again ; and so the process goes on, till the Pb is ex- 
hausted. White-lead is often adulterated 
with heavy spar, gypsum, etc. 

Lead Acetate, Sugar of Lead, has a 
sweet, pleasant taste, but is a virulent 
poison. Its antidote is Epsom salt, which 
forms an insoluble lead sulphate. H 2 dis- 
solves sugar of lead readily. If a piece of 
Zn, cut in small strips, be suspended, in a 
bottle filled with a solution of lead acetate, 
the Pb will be deposited upon it by voltaic action in 
beautiful metallic spangles, forming the " lead-tree." 



A. — An earthen 

pot. 
Li. — A coil of 

lead, 
y. — A solution 

of vinegar. 



Fig. 65. 




* Example : Heat a bit of lead upon charcoal in the oxidizing flame of 
the blow-pipe. A film of the suboxide forms first, then a yellow crust 
of the oxide. 



GOLD. 165 

THE NOBLE METALS. 

JJu, ^g, fy Hg } Pdj If, Os, Ru, aijd Ro. 



GOLD. 

Symbol, Au Atomic Weight, 197,2 Specific Gravity, 19.84. 

Fusing Point, about 2012° F, or 1100° C, 

Sources. — Au is sometimes found in masses called 
nuggets, but generally in scattered grains, or scales. 
As the rocks in which it occurs disintegrate by the 
action of the elements and form soil, the Au is 
gradually washed into the valleys below, and thence 
into the streams and rivers where, owing to its 
specific gravity, it settles and collects in the mud 
and gravel of their beds.* 

Preparation. — As the metal is thus found native, 
the process is purely mechanical, and consists simply 
in washing out the dirt and gravel in wash-pans, 
rockers, sluices, f etc, at the bottom of which the Au 
accumulates. In the quartz-mills, the rock is thrown 
into troughs of water where by heavy stamps the 

* In California, Au is found in the detritus (small particles of rock 
worn off by attrition) of granite and quartz. It occurs in the gravel of 
hills from the surface to the " bed-rock," sometimes a depth of 300 to 500 
feet; in the alluvial soil of the plains, and even in vegetable loam among 
the roots of grass. 

t Sluices are generally used in California. These are gently inclined 
troughs, sometimes extending for miles. Across the bottom are fastened 
low wooden bars, called riffles, above which quicksilver is placed. The dirt 
is shoveled into these sluices, or the auriferous hills are cut down, dis- 
solved, and washed through them by powerful streams of water, which are 
constantly running. The H a O floats off the debris, while the Hg catches 
the gold. 



166 INORGANIC CHEMISTRY. 

ore is crushed to powder. As the thin liquid mud 
thus formed splashes up on either side, it runs over 
broad, metallic tables covered with Hg; or is washed 
through a fine wire-screen, and carried to the 
" amalgamating-pans " by a little stream of water. 
The Hg unites with the particles of Au and forms 
with them an amalgam (a compound of mercury 
and a metal). Hg is easily separated from Au by dis- 
tillation,* and collected to be used again. 

Quartation. — Au is commonly found alloyed with 
Ag. The Ag is then dissolved out by HN0 3 . There 
must be at least three parts of Ag to one of Au, else 
the gold will protect the silver from the action of 
the acid. Au is also found alloyed with copper, iron, 
and other metals, f 

Properties. — Pure Au is nearly as soft as Pb. It is 
extremely malleable J and ductile. Its solvent is 

* The larger part of the Hg is separated from the amalgam by pressure in 
canvas or buckskin bags, the liquid Hg escaping through the pores, while 
the amalgam is left quite dry. The latter is then " retorted " for distillation. 

t "In works for the refining of gold and silver, the processes can be 
conducted economically only when great care is taken to avoid the loss of 
any particles of the precious metals. Thus all the old crucibles are ground 
and treated with mercury, and after as much gold and silver as possible 
have been extracted, the residues are sold to the sweep-washers, who extract 
a little more by melting with lead. The very dust off the floors is collected 
and treated in a similar way.'"— Bloxam. 

t For a description of the process of making gold-leaf, see "Physics," page 
20. " When one of these leaves is held up to the light, it exhibits a beauti- 
ful green color, and if it be rendered still thinner, either by beating, or by 
floating it upon a very weak solution of potassium cyanide, which slowly 
dissolves it, it transmits, when taken upon a glass plate and held up to the 
light, a blue, violet, or red light, in proportion as its thickness diminishes. 
Even when it is so transparent that one may read through it, the yellow 
color and luster of the gold are still visible by reflected light. These vary- 
ing colors of finely-divided gold are turned to account in the coloring of 
glass and in painting on porcelain." 



SILVER. 



167 



aqua regia. It does not oxidize at any temperature 
and, on account of the resistance it offers to corro- 
sion, it was anciently called the king of the metals. 



SI L VE R. 



Synjbol, kg . . , . Atonjic Weight,108 .... Specific Gravity, 10.57. 
Fusiijg Poiqt, 1904° F. or 1040° C. 

Sources. — Silver is found throughout the West in 
a great variety of forms — most commonly, however, 

Fig. 66. 




Separation of Pb from Ag. (See Bloxam's Metals,) 

combined with S, as Mack sulphide, Ag 2 S ; with CI, 
forming horn-silver, AgCl; with S and As or Sb, 



168 INORGANIC CHEMISTRY. 

making ruby-silver, and also associated with Pb in 
ordinary galena. 

Preparation. — 1st. The sulphide is treated as fol- 
lows : The ore is crushed into fine powder and then 
roasted with common salt. The CI of the salt unites 
with the Ag, forming silver chloride. This is next 
put into a revolving cylinder with H 2 0, Hg, and iron 
scraps. The Fe removes the CI from the silver, when 
the Hg takes it up, thus forming an amalgam of Hg 
and Ag. From this the Ag is easily obtained by dis- 
tilling off the Hg, as in the extraction of gold.* 2d. 
From horn-silver, AgCl, the process is like the latter 
part of that just described. 3d. From lead the Ag can 
be profitably obtained when there are only two or 
three ounces in a ton. The alloy of the two metals 
is melted, and then slowly cooled. Crystals of 
almost pure Pb appear, and are skimmed out as fast 

as formed, thus leaving an alloy much 
I(T ' richer in silver. (See Fig. 66.) The 

^^HP last portions of Pb are removed from 

i"flh^l8HBi this alloy by " cupellation." 

Cupellation. — A cupel (cupella, a 

small cup) is a shallow vessel, made of 
bone ashes. In this the Ag, debased with Pb and 
other impurities, is exposed to a red heat, so as to 
melt the metals, while a current of hot air plays 

* "The process of reducing silver ores at the West is unlike the G-erman 
method given above, and varies in different localities. One plan is as fol- 
lows : The powdered and roasted Ag 2 S is placed with Hg in iron pans, five 
feet in diameter and two feet deep. Here it is kept heated by steam to 
180°, and agitated by revolving stirrers. The chloride is not roasted, but is 
simply powdered, and then worked in the pans for an hour with NaCl be- 
fore adding the Hg."— Stevenson. 



SILVER. 



169 



upon the surface. The Pb oxidizes to PbO, and is 
absorbed by the porous cupel. The mass appears 
soiled and tarnished, but the refiner keeps his eye 
upon it as the process continues, watching eagerly, 
until at last there is a brilliant play of colors — in a 



Fig. 68. 




Cupels in the Furnace. 

moment more the last film of oxide disappears, and 
the brilliant surface of the pure silver lies gleaming 
at the bottom.* 

* See Malachi iii. 3. During the cooling of the cake of Ag, some very 
remarkable phenomona are observed. "When a thin crust of metal has 
formed upon the surface, the Ag beneath it assumes the appearance of 
boiling, and the crust is forced up into hollow cones about an inch high, 
through which the melted Ag is thrown out with explosive violence, some of 
it being splashed against the arch of the furnace, and some solidifying into 
most fantastic tree-like forms several inches in height. This behavior of 
Ag has been shown to be due to its property of mechanically absorbing O, 
at a temperature above its melting-point, which it gives off as it approaches 
the point of solidification, the escaping gas forcing up the crust of solid Ag 
formed upon the surface. 



170 INORGANIC CHEMISTRY. 

Properties. — Ag is the whitest of the metals. It is 
malleable and ductile, and is of all the metals the 
best conductor of electricity. It expands at the 
moment of solidification, and therefore can be cast. 
It has a powerful attraction for S, forming silver 
sulphide. Silver spoons and door-knobs are tarnished 
by the minute quantities of H 2 S present in the air.* 
The best solvent of Ag is HN0 3 . The test of Ag in 
solution is HC1, which forms a cloudy precipitate of 
silver chloride. A solution of silver coin is blue, 
from the Cu it contains. Standard silver is whitened 
by being heated until the of the air has converted 
a little of the Cu on the outside into CuO, which is 
dissolved by immersing in dilute H 2 S0 4 or NH 4 0H. 
The film of nearly pure Ag which then remains at the 
surface exhibits a want of luster and is called dead 
or frosted silver. It is brightened by burnishing. 

Compounds. — Silver Nitrate, AgN0 3 , is sold in 
small, round sticks as lunar caustic, used as a 
cautery. It stains the skin and all organic matter 
black, especially when exposed to the light, owing 
to the formation of metallic silver, f Many hair-dyes 
and indelible inks contain AgN0 3 . It is also the basis 

* " Those who have visited sulphur springs know the propriety of care- 
fully protecting their watches, and of never wearing silver ornaments to 
the hot baths. Ag 2 S is very easily dissolved by a little dilute ammonia 
(1 part of NH 4 OH to 20 of H 2 0), which is therefore used for cleaning silver 
door-knobs. — Oxidized silver, as it is erroneously called, is made by immers- 
ing articles of silver in a solution obtained by boiling sulphur with potash, 
when the metal becomes coated with a thin film of sulphuret of silver."— 
Bloxam. 

t The stain of silver nitrate may be removed by a strong solution of 
potassium iodide or the poisonous potassium cyanide. (See caution on page 
290.) 



SILVER. 171 

of photography (light-drawing) and daguerreotyping,* 
which are both founded upon essentially the same 
principles. The general outlines of the photographic 
process are as follows: 1. Iodized collodion f is poured 
upon a clean glass plate, which, on evaporation, it 
covers with a transparent film. 2. The plate is put 
in the " nitrate of silver bath," J where the salt of 
silver is absorbed by the collodion film and changed 
to brom-iodide of silver. The plate is now ready for 
the picture. After the sitting, the plate is taken, 
carefully protected from the light, to the operator's 

* The daguerreotype is named from M. Daguerre, the discoverer, who 
received a pension of 6,000 francs per year from the French government. 
A plate of Cu, plated on one side with Ag, is exposed to the vapor of I and 
Br until a compound of brom-iodide of silver is formed upon the surface. 
This is extremely sensitive to the light, hence the process is always con- 
ducted in a dark closet. The plate is then carried, carefully covered, to the 
camera, and placed in the focus, where the rays of light from the person 
whose "picture is being taken 1 ' fall directly upon it. These rays decompose 
the brom-iodide of silver. The amount of this change is directly proportional 
to the intensity of the light that is reflected from different parts of the 
person to form the image in the camera. A white garment reflects much 
of the light that falls upon it, so the corresponding part of the plate will 
be very much changed. A black garment reflects but little light, so that 
part will not be changed at all. The different colors and shades reflect 
varying proportions of light, and so influence the plate correspondingly. 
When the plate is taken out of the camera, it is carefully covered again and 
carried into the dark closet. No change can be detected by the eye ; but 
on exposure to the vapor of Hg, wherever the Ag has been freed, the Hg 
will combine with it, forming a whitish amalgam, but it has no effect on 
the rest of the plate. The picture thus treated comes forth nearly perfect 
in its lights and shades. The undecomposed brom-iodide of silver is re- 
moved by a solution of sodium hyposulphite. A solution of gold chloride 
and sodium hyposulphite is then poured upon the plate and warmed. This 
golden varnish finishes the picture. 

t Iodized collodion is composed of gun-cotton dissolved in alcohol and 
ether, to which are added ammonium iodide and cadmium bromide, or 
similar salts. 

X The nitrate of silver bath contains nitrate of silver and iodide of silver 
in solution, and is acidulated with nitric acid. 



172 INORGANIC CHEMISTRY. 

room. Here the picture is, 3, developed by a solution 
of ferrous sulphate (green vitriol, see p. 158) or pyro- 
gallic acid (see p. 238) ; at the right stage the liquid 
is washed off, and the operation checked. 4. It is 
fixed with a solution of sodium hyposulphite, which 
dissolves the unaltered brom-iodide of silver. 5. It is 
washed, dried, and coated with amber varnish to 
preserve the film from accidental injury. The 
"negative" is now completed, and is a correct like- 
ness, only the lights and shades are reversed. From 
this the pictures are, 1, "printed" by placing the 
negative upon a sheet of prepared paper,* and expos- 
ing it to the sun's rays. When the colors are suffi- 
ciently deepened, the picture is, 2, toned in the 
"toning-bath," which contains a little "bicarbonate 
of soda" and a minute quantity of gold chloride; 
3, fixed, by sodium hyposulphite which dissolves the 
unaltered AgCl ; 4, thoroughly washed in water fre- 
quently renewed; and, lastly, dried and mounted on 
card-board. The thoroughness of the third and fourth 
processes has much to do with the permanence of 
the picture. If any of the chloride or the compound 
formed by the hyposulphite be left, it will cause 
fading or discoloration. 

Silver Chloride, AgCl, occurs naturally as horn- 
silver, and falls as a white curdy precipitate when 
H CI or a soluble chloride (e. g., NaCl) is mixed with a 
silver solution. 

* This paper is "sensitized" by floating it on a solution of sodium 
chloride, and then on one of silver nitrate, thus filling the pores of the 
paper with the silver chloride, which is extremely sensitive to light. 



PLATINUM. 173 

P LAT I N U M. 

Synjbol, Pt. ... Atomic Weight, 194.3 .... Specific Gravity, 21.53. 
Fusing Point, about 3632° F. or 2000' C. 

Source. — Pt* is chiefly found in the Ural Mount- 
ains, where it occurs in alluvial deposits, usually in 
small, flattened grains,! which contain Au, Pd, Rh, 
Ru, Ir, and Os, as well as Fe. Cu, etc., besides the Pt. 

Preparation. — The "ore," as it is called, is sepa- 
rated from the earthy particles by washing, and the 
Pt extracted by a rather complicated process. 

Properties. — Pt resembles Ag in its appearance. It 
is one of the most ductile metals, wire having been 
made from it so fine as to be invisible to the naked 
eye.J It is soluble in aqua regia, but not in the simple 
acids. It does not oxidize in the air, is one of the 
most infusible of metals, and can be melted only by 
the heat of the compound blow-pipe or voltaic 
battery. In the arts it is fused in the former 
manner. These properties fit it for making crucibles 
that are invaluable to the chemist. 

Platinum Sponge (see page 42) is made by heat- 
ing the double chloride of Pt and NH 4 . 

Platinum Black is obtained by the action of re- 
ducing agents upon Pt solutions. 

* The word j)lati nv.m signifies "little silver.' 1 
t The largest nugget ever found weighed about 18 lbs. 
% Wollaston's Method, as it is called, consists in covering fine platinum 
wire with several times its weight of Ag. and then drawing this through 
the plates used for drawing wire until the finest hole is reached, when the 
wire is placed in HX0 3 , which dissolves the Ag and leaves the Pt intact. 
This, in the form of the finest wire known, may be found in the solution 
by means of a microscope. (See 4 * Physics," p. 19.) 



174 INORGANIC CHEMISTRY. 



MERCURY. 

Symbol, Hg . , . . Atonjic Weight, 200 ... . Specific Gravity, 13.6. 
Melting (Freezing) Poiijt,— 39° C Boiliijg Poiijt, 680° F. or 360° C, 

Mercury is also called quicksilver, because it rolls 
about as if it were alive, and was supposed by the 
alchemists to contain silver. It was known very 
anciently, and the mines of Spain were worked by 
the Romans. 

Source. — Cinnabar, HgS, a brilliant red ore, is the 
principal source of this metal.* 

Preparation. — Hg is readily prepared by heating 
HgS in a current of air. The S passes off as S0 2 , while 
the Hg volatilizes and is condensed in earthen pipes. 

Properties. — Hg emits a vapor at all temperatures, 
and this vapor is poisonous. The solvent of Hg is 
HN0 3 . It forms an amalgam f with gold or silver. 
This is its most singular property. A gold leaf 

* Hg is found native in Mexico in very small quantities, where the 
mines are said to have been discovered by a slave, who, in climbing a 
mountain, came to a very steep ascent. To aid him in surmounting this, 
he tried to draw himself up by a bush which grew in a crevice above. The 
shrub, however, giving way, was torn up by the roots, and a tiny stream, 
of what seemed liquid silver, trickled down upon him. 

t " Several years ago, while lecturing upon chemistry before a class of 
ladies, we had occasion to purify some quicksilver by forcing it through 
chamois skin. The scrap of leather remained upon the table after the 
lecture, and an old lady, thinking it would be very nice to wrap her gold 
spectacles in, accordingly appropriated it to this purpose. The next morn- 
ing she came to us in great alarm, stating that the gold had mysteriously 
disappeared, and nothing was left in the parcel but the glasses. Sure 
enough, the metal remaining in the pores of the leather had amalgamated 
with the gold, and, entering, destroyed the spectacles. It was a mystery, 
however, which we could never explain to her satisfaction."— J. R. Nichols 
in Fireside Science. 






MERCUEY. 175 

dropped upon mercury disappears like a snow-flake 
in water. Particles of Ag or Au, too fine to be seen by 
the eye, will be found by Hg and gathered from a 
mass of ore. 

Uses. — Hg is extensively employed in the manu- 
facture of thermometers and barometers ; for silver- 
ing mirrors ; * and for extracting the precious metals 
from their ores. 

The action of Hg on the human system is too 
well known to need description. "In its metallic 
state, Hg has been taken with impunity in quantities 
of a pound weight" ("American Cyclopaedia"), but 
when finely divided, as in vapor, mercurial ointment, f 
or "blue-pill," its effects are marked. It renders the 
patient extremely susceptible to colds ; acts, as is 
generally thought, upon the liver, increasing the se- 
cretion of bile, and repeated doses produce "salivation." 

Compounds. — Mercuric Oxide, HgO, "red precipi- 

* Mirrors were anciently made of steel or silver, highly polished. They 
were very liable to rust and tarnish, and so a piece of sponge, sprinkled 
with pumice-stone, was suspended from the handle for rubbing the mirror 
before use. Seneca, in lamenting over the extravagance of his time among 
the old Romans, says : " Every young woman nowadays must have a silver 
mirror.'" The process of "silvering " ordinary mirrors is briefly as follows: 
Tin-foil is first spread evenly upon a marble table, and then the Hg is care- 
fully poured over it. The two metals combine, forming a bright amalgam. 
A clean, dry plate of glass is then carefully pushed forward over the table 
so as to carry the superfluous Hg before it, and also prevent the air from 
getting between the glass and the amalgam. Weights are afterward added 
to cause the film to cling more closely. In twenty-four hours the plate is 
removed, and in three or four weeks is dry enough to be framed. When 
we look in a mirror we rarely realize what it has cost others to thus 
minister to our comfort. The workmen are short-lived. A paralysis some- 
times attacks them within a few weeks after they enter the manufactory. 
Silver is now often used in backing mirrors. It is harmless. 

t This is vulgarly called " anguintum," which may be a corruption of 
the Latin term unguentum (unguent). It is used in cutaneous diseases. 



176 INORGANIC CHEMISTRY. 

tate," is interesting, as the substance from which 
Priestley first obtained gas. 

Mercurous Chloride, HgCl, Calomel, is a white 
powder used in medicine. It can be easily distin- 
guished from corrosive sublimate, since it is insoluble 
in H 2 0, and hence tasteless. 

Mercuric Chloride, HgCl 2 , Corrosive Sublimate, is 
a heavy, white solid, soluble in H 2 0, and has a 
burning metallic taste. It has powerful antiseptic 
properties, and is used to preserve specimens in 
natural history. It is a deadly poison. Its antidote 
is white of eggs, milk, etc. 

Mercuric Sulphide, HgS, " Vermilion" is made by 
subliming a previously fused mixture of Hg and S. 
It is used as a pigment. 



THE ALLOYS. 

These are very numerous, and many of them pos- 
sess properties so different from their elements that 
they seem like new metals. The color and hard- 
ness are changed, and sometimes the melting point 
is below that of any one of the constituents. The 
proportions of the metals used vary. The following 
is a fair average : 

Type-metal* contains 50 per cent, of Pb, equal 
parts of Sn and antimony,f and a little Cu. 

* The composition of type-metal varies considerably. It is sometimes 
made of Pb and antimony alone ; and the proportions of these two metals 
are different for large and small type— the small type containing a larger 
amount of antimony to make them harder. 

t Antimony was discovered by Basil Valentine, a monk of Germany, in 



THE ALLOYS. 177 

Pewter contains 9 parts of Sn and 1 of Pb. 

Britannia consists of 9 parts of Sn, 1 of Sb, and 
usually about 3 per cent. Zn, and 1 per cent. Cu. 

Brass is about 2 parts of Cu and 1 of Zn. 

German Silver contains 50 parts of Cu, 25 of Zn, 
and 25 of Ni* (brass whitened by nickel). 

Soft Solder, used by tinsmiths, is made by melt- 
ing Pb and Sn together, the usual proportion being 
half-and-half. 

Hard Solder is composed of Cu and In. 

Wood's Fusible Metal melts at 158° F. ; and 
spoons made of it will fuse in hot tea. It can be 
melted in a paper crucible over a candle. It consists 
of Bi,f Pb, Sn, and Cd. Yet the first metal melts at 
518° F., the second at 635°, the third at 446°, and 
the fourth at 599°. 

Bronze is 3 parts of Cu and 1 part of Sn. 

Gold is soldered with an alloy of itself and Ag ; 
Silver, with itself and Cu ; Copper, with itself and 

the fifteenth century. It is a brittle, bluish-white metal, with a beautiful 
laminated, star-like, crystalline structure. Its chief use is as an alloy for 
type-metal, Britannia- ware, etc., one of its most important properties being 
that it expands in c oling from G usion, and thus makes a very sharp cast- 
ing. Its test is H 2 S, which throws down a brilliant orange-colored precip- 
itate. Melt a small fragment of Sb before the blow-pipe, and throw the 
melted globule upon an inclined plane. It will instantly dart off in minute 
spheres, each followed by a long trail of smoke. 

* Ni, like Co, is a constituent of meteorites. It is mined in Pennsyl- 
vania, Canada, New Caledonia, etc., to make into coins. Formerly, its 
principal use was in GJ-erman silver, but of late it has been employed ex- 
tensively in the manufacture of the best plated-ware. (See " Physics," page 
238.) Its silvery whiteness, when pure, its high polish, which often lasts for 
years, and its hardness, almost equal to that of steel, eminently fit it for the 
plating of mathematical and other delicate instruments. The salts of Ni 
have a handsome green tint. 

t Bismuth closely resembles Sb. Its chief use is in making fusible 
alloys. Its salts are employed in making cosmetics and as medicines. 



178 INORGANIC CHEMISTRY. 

Zn : the principle being that the metal of lower 
fusing point causes the other to melt more easily. 

Coin. — The precious metals, when pure, are too 
soft for common use. They are therefore hardened 
by other metals. The gold coin of the United States 
consists of 9 parts of gold and 1 of alloy. The alloy 
is chiefly Cu ; but gold coin always contains a little 
Ag, which was not separated from the Au in the 
quartation (p. 166). Silver coin is 9 parts of Ag and 
1 of Cu. The nickel coin is 75 parts of Cu and 25 
of Ni. Cu being cheaper than Ni, it is used to make 
the coin larger. The term carat, applied to the 
precious metals, means -^ part. Therefore, gold 18 
carats fine contains -J-f of gold and ^ of alloy. 

Shot is an alloy of something less than 1 part of 
As to 100 of Pb. The manufacture is carried on in 
what are called " shot-towers," some of which are two 
hundred and fifty feet high. The alloy is melted at 
the top of the building, and poured through colan- 
ders. The metal, in falling, breaks up into drops, 
which take the spherical form (see " Physics," pages 
44 and 192), harden, and are caught at the bottom 
in a well of water, which cools the shot and also 
prevents their being bruised in striking. The shot 
are dipped out, dried, and then assorted, by sifting 
in a revolving cylinder, which is set slightly inclined 
and perforated with holes, increasing in size from the 
top to the bottom. The shot being poured in at the 
top, the small ones drop through first, next the larger, 
and so on, till the largest reach the bottom. Each 
size is received in its own box. Shot are polished by 



REVIEW OF THE METALS. 179 

being agitated for several hours with black-lead, in a 
rapidly-revolving wheel. They are finally tested by 
rolling them down a series of inclined planes placed 
at a little distance from each other. The spherical 
shot will jump from one jjlane to the next, while the 
imperfect ones will fall short, and drop below ; or 
sometimes, by rolling down a single inclined plane, 
the spherical ones will go to the bottom, while the 
imperfect ones roll off at the sides. 

Or-Molu is a beautiful alloy of Cu and Zn resem- 
bling red gold, but it soon tarnishes by exposure to 
the air. 

Aluminium Bronze, or gold, is an alloy of Al and 
Cu. It is elastic, malleable, and very light. It 
strikingly resembles gold, and is sometimes used in- 
stead of that costly metal. 



REVIEW OF THE PROPERTIES 
OF THE METALS. 

Oxidation. — K and Na have an intense attraction 
for and other elements, and are never found ex- 
cept in combination, while Au, Pt, etc., have little 
affinity for other substances, and are therefore found 
native. 

Density. — Li is lighter than any known liquid. K, 
Na, and Li float upon H 2 0, while Pt is over twenty- 
one times and Os over twenty-two times as heavy as 
H 2 0. 

Melting Point. — Hg is liquid at all ordinary tem- 
peratures. K and Na melt beneath the boiling point 



180 INOKGANIC CHEMISTRY. 

of H 2 ; Zn below a red heat, and Cu above ; Co, Ni, 
and wrought iron require the greatest heat of the 
forge (4000° F.), while Pt and Os melt only in the 
flame of the oxy-hydrogen blow-pipe. Sn melts at 
the lowest temperature (446°) of any of the ordinary 
metals. 

Color. — The most common color is white, of vary- 
ing shades. It is nearly pure in Ag, Pt, Cd, and Mg ; 
yellowish in Sn ; bluish in In and Pb ; gray in Fe, 
and reddish in Bi. Cu is a full red, and Au a bright 
yellow. 

Malleability. — Au, Ag, Al, and Cu are the most malle- 
able of the metals ; Au, Ag, and Pt are the most ductile. 

Brittleness. — Sb and Bi may be easily powdered ; 
Zn may be broken with more difficulty, while the 
fibrous metals are exceedingly tough. 

Tenacity. — Steel is the most, and lead the least, 
tenacious of the metals ; the proportion being as 
1 to 42. 

Special Properties. — Certain of the metals are 
valuable because of their peculiar properties. Thus, 
Hg, because it will form an amalgam, and is a liquid 
at all ordinary temperatures ; Sb, because it hardens 
Pb and Sn ; Bi and Cd, because they render Pb and 
Sn more fusible; Ni, because it whitens Cu ; Mg, for 
its brilliant light ; Au, for its rarity and luster ; Fe, 
for the diverse properties it can assume in wrought 
and cast iron and in steel, and because it is the only 
metal which can be used for the magnetic needle 
and electro-magnet ; Cu, for its ductility and its con- 
ductivity of electricity ; and Pt, for its infusibility. 



PRACTICAL QUESTIONS. 181 



PRACTICAL QUESTIONS. 

1. Pb is softer than ITe ; why is it not more malleable ? 

2. What is the cause of the changing color often seen in the scum on 
standing water? 

3. How can the spectra of the metals be obtained? 

4. Ought cannon, car-axles, etc., to be used until they break or wear 
out? 

5. "Why is "chilled iron" used for safes? 

6. Does a blacksmith plunge his work into water merely to cool it? 

7. What causes the white coating made when we spill water on zinc? 

8. Is it well to scald pickles, make sweetmeats, or fry cakes in a brass 
kettle ? 

9. What danger is there in the use of lead pipes? Is a lining of Zn or 
Sn a protection? 

10. Is water which has stood in a metal-lined ice-pitcher healthful? 

11. If you ask for "cobalt" at a drug-store, what will you get? If for 
11 arsenic " ? 

12. What two elements are fluid at ordinary temperatures? 

13. Should we touch a gold ring to mercury?* 

14. Why does silver blacken if exposed to the air? 

15. Why does silver tarnish more rapidly where coal is used for fires? 

16. WTiy is a solution of a silver coin blue? 

17. Why will a solution of silver nitrate curdle brine? 

18. Why does writing with indelible ink turn black when exposed to 
the sun, or to a hot iron? 

19. WTiat alloys resemble gold? 

20. Why does a fish-hook "rust out" the line to which it is fastened? 

21. Why do the nails in clapboards loosen? 

22. Show that the earth's crust is mainly composed of burnt metals. 

23. What kind of iron is used for an electro-magnet? For a magnetic 
needle ? 

24. WTiy does a "tin" pail so quickly rust out when once the tin is 
worn through? 

25. Why is the zinc oxide found in 3STew Jersey red, when zinc rust is 
white? 

26. Should we filter a solution of permanganate of potash through 
paper? 

27. Why are wood, cordage, etc., sometimes soaked in a solution of cor- 
rosive sublimate? 

28. Why does the white paint around a sink sometimes turn black? 
What danger does this indicate? 

* If the surface is only whitened, the Hg may be removed with dilute 
HN0 3 , and the ring be polished to look as before. The Hg will soon pene- 
trate the gold, and render it brittle. 



182 INORGANIC CHEMISTRY. 

29. Why is aluminium, rather than platinum, sometimes used for 
making the smallest weights? 

30. How would you detect the presence of iron particles in black sand? 

31. Which metals can be welded? 

32. When the glassy slag from a blast-furnace has a dark color, what 
does it show? 

33. In welding iron, the surfaces to be joined are sometimes sprinkled 
with sand. Explain. 

34. What is the difference between an alloy and an amalgam? 

35. Steel articles are blued to protect from rusting, by heating in a 
sand-bath. Explain. 

36. Give the formulas for copperas and white lead. 

37. Why is Hg used for filling thermometers? 

38. What oxides are formed by the combustion of Na, K, Zn, S, Ee, Pb, 
Cu, P, etc? Which are" bases? Anhydrides? Grive the common name of 
each. 

39. Is charcoal lighter than H 2 0? 

40. Name the "vitriols." 

41. Is Mg univalent or bivalent? Zn? 

42. Name some bibasic acid. 

43. Name a neutral salt. An acid salt. 

44. Calculate the percentage of water contained in crystallized copper 
sulphate ; in sodium sulphate ; in calcium sulphate ; in alum. 

45. What is the test for Ag? Cu? 

46. What weight of crystallized " tin salts " (SnCl 2 ,2H 2 0) can be pre- 
pared from one ton of metallic tin ? 

47. 100 parts by weight of silver yield 132.87 parts of silver chloride. 
Given the atomic weight of chlorine (35.4), required that of silver. 

48. What is the composition of slaked lime? 

49. How is ferrous sulphate obtained? How many tons of crystals can 
be obtained by the slow oxidation of 230 tons of iron pyrites containing 
37.5 per cent, of sulphur? 

50. Required 500 tons of soda crystals ; what will be the weight of salt 
and pure sulphuric acid needed? 

51. Describe the uses of lime in agriculture. 

52. How many tons of oil of vitriol, containing 70 per cent, of pure 
acid (H 2 S0 4 ), can be prepared from 250 tons of iron pyrites, containing 42 
per cent, of sulphur? 



III. 



Organic Chemistry. 



" Thus the Seer, 
"With vision clear, 
Sees forms appear and disappear. 
In the perpetual round of strange, 
Mysterious change 

From birth to death, from death to birth, 
From earth to heaven, from heaven to earth; 
Till glimpses more sublime 
Of things, unseen before, 
Unto his wondering eyes reveal 
The Universe as an immeasurable wheel 
Turning f orevermore 
In the rapid and rushing river of Time." 

LOXGFELLOW. 



ORGANIC CHEMISTRY. 



INTRODUCTION. 

Organic Chemistry is the chemistry of the com- 
pounds of carbon. It originally meant the chemistry 
of organized bodies, animal and vegetable, and their 
products. As was stated in the introduction (p. 7), 
it was formerly believed that the so-called organic 
substances formed a group entirely distinct from the 
inorganic, because they could be produced only by 
the agency of life. But in 1828, Wohler, a German 
chemist, discovered that an organic compound, urea, 
could be artificially prepared. Since then a very 
large number of compounds have been made, which 
had before been obtained only from animal and 
vegetable substances ; among others such well-known 
ones as alcohol, tartaric acid, glycerin, indigo, aliza- 
rin (the coloring matter of madder), and gallic acid.* 

There is, however, one class of organic substances, 
the organized bodies, such as muscular tissue, nerve 
structure, ligneous fiber, no one of which has yet 
been made in the chemist's laboratory ; nor is there 
any promise in the past development of organic 
chemistry, wonderful as that development has been, 

* " There is but little doubt, as new methods are discovered, and our 
knowledge of the carbon compounds increase, that we may eventually be 
able to produce synthetically even the most complex. "—Miller. 



186 ORGANIC CHEMISTRY. 

that these substances can be artificially made. These 
organized bodies are formed from inanimate matter, 
by the action of life, and are constantly under- 
going rapid change. 

While other substances are formed and remain 
fixed in one state under the influence of chemical 
affinity, the organized bodies grow rapidly, change 
constantly, and when life ceases, as rapidly decay. 
Owing to their complex structure, and the presence 
in many of them of the negative N, they form most 
unstable compounds. In this we find the cause of 
their quick decay. The vital principle alone holds 
them together, and the instant that is removed, dis- 
integration sets in, the tendency of the component 
elements being to seek new affinities and form new 
compounds. 

Composition of Organic Substances. — All organic 
substances contain C. One large and important class 
contain C and H alone ; many consist of the three 
elements C, H, and 0; others consist of C, H, 0, and 
N ; while a few contain also S and P. In the labo- 
ratory, organic compounds have been made which 
contain many other elements ; but those given above 
exhaust the variety of elementary constitution in 
most natural organic substances. 

The Number of Carbon Compounds greatly ex- 
ceeds that of all the other substances combined, and is 
constantly increasing. The labor of modern chemists 
is largely devoted to the subject, and the field opens 
and broadens with every discovery. That such a vast 
number of different compounds of carbon with two 



INTRODUCTION. 187 

or three other elements should exist, seems at first 
very puzzling. In inorganic chemistry, the number 
of compounds which any single element can form 
with all the others, is very limited. The explanation 
must be looked for, first of all, in a peculiarity of C. 
We have already learned that C is quadrivalent, 
forming a compound with four atoms of H, — CH 4 . If 
we use a dash to indicate each unit of valence, this 

formula may be written : 

H 

C^H 4 , or H-C-H. 

Another compound of C and H is C 2 H 6 . The only 
way in which this can be expressed in detail, ac- 
counting for the quadrivalency of C in both atoms, 

is H 3 =C-C=H 3 , or 

H 

H-C-H 

H-C-H 

A 

which shows the C atoms linked together by one 
dash or "bond" of valence, and thus capable of hold- 
ing three, and only three, atoms of H apiece. In the 
same way, C 3 H 8 equals H 3 =C-C=H 2 -C=H 3 ; C 4 H| equals 
C=H 3 -C=H 2 -C=H 2 -C=H 3 , etc. 

In another series of hydrocarbons, a linkage be- 
tween two atoms of C by double bonds occurs ; thus, 
C 2 H 4 (see p. 72), equals H 2 =C=C=H 2 ; C 3 H 6 equals H 2 = 
C=C-H-C=H 3 , etc. In still another series, there is a link- 
age by three bonds; thus, C 2 H 2 equals H-C=C-H, etc. 



lob ORGANIC CHEMISTRY. 

It is through this facility with which C atoms 
link together in chains, that the number of different 
organic compounds is in part explained. When we 
consider further that one or more H atoms in each 
of these hydrocarbons may be replaced by 0, N, or 
groups containing 0, N, H, and C, such as OH, N0 2 , 
CO, NH 2 , CN, CH 3 , etc., etc., the great variety of or- 
ganic substances ceases to be so surprising. 

Isomerism. — Isomeric compounds are those which 
consist of the same elements in the same proportion. 
Thus two compounds are known which have the 
same formula, C 2 H 4 C1 2 , and there are many similar 
cases. The difference between such compounds is 
believed to lie in a dissimilar grouping of the atoms 
about one another, as the same pieces upon a 
checker-board may be variously arranged ; or as the 
letters p-l-e-a may also spell 1-e-a-p, or p-e-a-1, or 
p-a-l-e ; and this difference finds expression in the 
constitutional formulas* of the substances. These 
formulas for the two compounds C 2 H 4 C1 2 , are: 

H H 

H-C-H H-C-Cl 

H-C-Cl and H-C-Cl 

l I 

CI H 

Complexity of Organic Molecules. — While inor- 
organic molecules consist of only a few atoms, and 
are therefore very simple in their construction, as : 

* These formulas must not be understood to represent in any sense the 
relative positwns of the atoms, but only the relations which they bear to one 
another, as shown by chemical reactions. 






PARAFFINES AND THEIR DERIVATIVES. 189 

H 2 0, C0 2 ; organic frequently contain a large number, 
and are extremely complex, as: Sugar = C, 2 H 22 0,,, 
having 45 atoms in a molecule; stearin = C 5 7H M0 6 , 
having 173 atoms; albumin=C7 2 H,| N, 8 S0 22 , having 
222 atoms, and perhaps even more. 



■» • ■* 



THE PARAFFINES AND THEIR 
DERIVATIVES. 

Marsh-gas, CH 4 (page 71), is the first member of 
a series of hydrocarbons whose common difference 
is CH 2 , and whose general formula may be written 
C n H 2n+2 . Paraffine {parum, little; affinis, affinity), 
so called because acids and bases have no effect 
upon it, is a mixture of hydrocarbons of this series, 
and gives it its name. All of the members of the 
paraffine series are characterized by their chemical 
indifference. In the table below are given the names 
and formulas of the lowest members of the series : 

PARAFFINE HYDROCARBONS, C n H 2n+2 . 

BOILING POINT. 

Methane (Marsh-gas) CH 4 Gas. 

Ethane C 2 H 6 Gas. 

Propane ... C 3 H 8 Gas. 

Butane C 4 H, i° 

Pentane C 5 H, 2 37 

Hexane C 6 H| 4 7 ! -5 

Heptane C 7 H, 6 98 

Octane C 8 H, 8 124 

Nonane C 9 H 20 150.8 

Etc. Etc. 



190 ORGANIC CHEMISTRY. 

There are also many other homologous series of hy- 
drocarbons. All the hydrocarbons in the foregoing list, 
and many more of the same series, occur in petroleum. 

Petroleum (petra, a rock ; oleum, oil) is probably 
the product of the distillation of organic matter be- 
neath the surface of the earth. It is not always 
connected with coal, as it is often found outside the 
coal-measures, as in New York and Canada. The dis- 
tillation must have taken place at a much greater 
depth than that at which the oil is now found, as it 
would naturally rise through the fissures of the rock 
and gather in the cavities above. Sometimes the oil 
has collected on the surface of subterranean pools of 
salt-water, so that after a time the oil is exhausted, 
and salt-water only is pumped up ; or if the well 
strikes the lower part of the cavity, the water will 
first be pumped, and afterward the oil. The crude 
oil from the well is purified by distillation, and treat- 
ment with concentrated H 2 S0 4 and alkalies. By the 
distillation it is divided into several parts (each a 
mixture of hydrocarbons), which are called cymo- 
gene, rhigoline, gasoline, naphtha, benzine, kerosene.* 



* Kerosene contains C 9 H 2 o— Ci 6 H 34 . Kerosene accidents generally rise 
from the presence of naphtha. This is a cheap, light, dangerous oil. Its 
vapor, however, is not explosive unless mixed with air. While a lamp, 
which contains adulterated kerosene, is burning quietly, there is no danger. 
The vapor rises from the oil, fills the empty space in the lamp, but being 
unmixed with air, can not explode. Let, however, a draught of cold air 
strike it, or carry it into a cold room— instantly the vapor will be condensed, 
the air will rush in, and a dangerous mixture be formed. Or when the 
light is extinguished at night the vapor will cool, air pass in, and a mixture 
be produced which will be ready to explode when the lamp is relighted. 
Properly purified, kerosene is no more explosive than water, and will even 
extinguish a flame applied to it at the ordinary temperature. Dr. Nichols 



PARAFFINES AND THEIR DERIVATIVES. 191 

The portion which is heavier than kerosene and boils 
at a higher temperature, yields lubricating oil and 
paraffine. 

Paraffine is a hard white, tasteless solid, melting 
at 44° C. It is used for making candles. It was dis- 
covered in 1830, as a product of beech-wood, but all 
of the paraffine of commerce is now obtained from 
petroleum. 

Bitumen or Asphaltum is another natural product, 
consisting chiefly of hydrocarbons. It is found in 
many parts of the world, sometimes pure, sometimes 
associated with various minerals. On the island of 
Trinidad is a lake of bitumen one and a half miles in 
circumference. Near the shore it is hard and com- 
pact, except in hot weather, when it becomes sticky. 
At the center it is soft, and fresh bitumen boils 
up to the surface. Asphaltum is found in immense 
quantities in California and in Canada. The bitu- 
men is used for the same purposes as pitch, which 
it closely resembles. It is a natural cement for 
laying stone or brick. It was used in building the 
walls of Babylon, for which purpose it was gathered 
from the fountain of Is, on the banks of the 
Euphrates. It was a prominent ingredient in the 
"Greek Fire," so much used by the nations of East- 
ern Europe in their naval wars, even as late as the 
fourteenth century. This consisted of bitumen, sul- 

gives the following simple test : Fill a bowl partly full of hot water. Insert a 
thermometer, and add cold water until the temperature is 110° F. Then pour into the 
bowl a spoonful of kerosene, and apply a lighted match. If it takes fire, the oil con- 
tains naphtha and is dangerous. See also an article in Popular Science Monthly 
for February, 1884. 



192 ORGANIC CHEMISTRY 

phur, and pitch, and was thrown through long, copper 
tubes, from hideous figures erected on the prow of 
the vessel. Bitumen is used in making pavements, 
as in Washington and Paris. 

Artificial Preparation of the Paraffines. — Methane, 
CH 4 , may be made by leading vapor of carbon disul- 
phide, CS 2 , mixed with H 2 S, over heated Cu : 

CS 2 + 2H 2 S + 8Cu = CH 4 + 4Cu 2 S. 

This reaction is very interesting, because it shows 
that it is possible to make this organic compound 
from the elements ; for CS 2 is prepared by the action 
of S vapor on C (page 110), and H 2 S can be produced 
by passing H through boiling S, or by burning S 
vapor in an atmosphere of H. 

The interest in this reaction becomes still greater 
when we learn that the other members of the series 
can be made from CH 4 . The way in which this may 
be done is the following: 1st. One atom of H in CH 4 
is replaced by an atom of CI, by the action of CI on 
CH 4 , giving the compound CH 3 C1. 2d. Two molecules 
of CH3CI are acted upon by Na: 

2CH 3 C1 + 2Na= 2NaCl + C 2 H 6 . 

This gives the second member of the series, 
ethane, in which two C atoms are linked. Then by a 
similar process the higher members may be formed, 
thus : 

CH 3 -CH 2 C1 + CH3CI + 2Na=2NaCl + C 3 H 8 ; 

and CH 3 -CH 2 -CH 2 C1 + CH 3 C1 + 2Na=2NaCl + C 4 H (0 , 

or, 2CH 3 -CH 2 C1 + 2Na=2NaCl + C 4 H I0 . 



OXYGEN COMPOUNDS OF PARAFFINES. 193 

THE OXYGEN COMPOUNDS OF 
THE PARAFFINES. 

THE ALCOHOLS. 

The alcohols are compounds which may be re- 
garded as hydrocarbons, in which the univalent 
group OH, called hydroxy!, has replaced H. It is con- 
venient to consider the alcohols as hydroxides of 
certain groups of radicals. Thus the alcohol derived 
from methane, CH 3 0H, is regarded as the hydroxide 
of the radical CH 3 , which is called methyl; the 
alcohol from ethane, C 2 H 5 OH, as the hydroxide of 
C 2 H 5 , ethyl, and so on; and the alcohols themselves 
are commonly called methyl alcohol, ethyl alcohol 
etc. These organic radicals can not be isolated. They 
are analogous to the inorganic group or radical NH 4 
(page 136), and the analogy of the alcohols to metal- 
lic hydroxides is readily seen. The alcohols, as well 
as the other derivatives of the paraffines, can be 
artificially prepared. 

Methyl Alcohol, CH 3 OH, is obtained as one of the 
products of the destructive distillation of wood.* It 
is a light, volatile liquid, which closely resembles 

* When hard wood, as beech or oak, is heated to a high temperature, 
with no O present, or an imperfect supply, it is decomposed ; the charcoal 
remains, while a large number of products is formed, among which are H, 
CO, C0 2 , H 2 0, CH 4 , methyl alcohol, acetic or pyroligneous acid, creosote, 
paraffine, tar, etc. 

Creosote (flesh-preserver) is a colorless, poisonous liquid, with a flavor of 
burnt wood. It has powerful antiseptic properties. It imparts to smoke a 
characteristic odor, renders it irritating to the eyes, and also gives to it the 
power which it possesses of curing hams, beef, etc. Much of that which is 
sold as creosote is carbolic acid. (See page 223.) 



194 OKGAISTIC CHEMISTRY. 

ordinary alcohol in all its properties. It is used in 
the manufacture of aniline dyes, in making var- 
nishes, and in spirit-lamps. 

Ethyl Alcohol, CH 3 — CH 2 0H, ordinary alcohol, is the 
best known and most important of the alcohols. It 
is formed by the fermentation of saccharine sub- 
stances, and prepared by distillation of the solution 
thus produced. In this way an alcohol of about 93 
per cent, can be obtained. In order to get "absolute" 
alcohol, this product must be mixed with quick-lime, 
which retains the water, and again distilled. Pure 
alcohol boils at 78° C, and has recently been frozen 
at a temperature of — 130.5° C. 

When it is exposed to the air the spirit evaporates, 
while moisture is absorbed from the atmosphere.* It 
burns without smoke and with great heat, owing to 
the abundance of H and deficiency of C, and is there- 
fore of much value in the arts. It is also of incal- 
culable importance as a solvent of many substances 
— roots, resins, fragrant oils, etc. 

Effects of Alcohol. — When pure it is a deadly 
poison. When diluted, as in the ordinary liquors, it 
is stimulative and intoxicating. Its influence is on 
the brain and nervous system ; — deadening the nat- 
ural affections, dulling the intellectual operations and 
moral instincts ; seeming to pervert and destroy all 
that is pure and holy in man, while it robs him of his 
highest attribute — reason. (See " Physiology," p. 150.) 



* The chemist discovers this when he neglects to put the extinguisher 
on his alcohol lamp, and finds that he can not relight it without moistening 
the wick with fresh alcohol. 



FERMENTATION. 195 



FERMENTATION. 

If a pure solution of grape-sugar be exposed to 
the air it will undergo no change ; but if there be 
added a little ferment,* or any albuminous substance 
(i. e., one containing N), in a decomposing state, it 
will immediately commence breaking up into new 
compounds. The fermentation is due to the presence 
of small organized bodies, which find materials for 
their sustenance in the solution, and in their growth 
overcome the equilibrium of the chemical forces, 
causing the large molecules to drop into smaller 
ones. There are different kinds of ferments, which 
cause different kinds of fermentation. 

1st. Alcoholic Fermentation. — In this, the grape- 
sugar is resolved into alcohol and carbon dioxide. 
The former remains in the liquid, while the latter 
escapes in little bubbles of gas. The reaction may be 
represented thus : C 6 H I2 6 = 2C 2 H 6 + 2C0 2 . 

2d. Acetic Fermentation. f — This often succeeds 

* "In many cases, spontaneous fermentation sets in without the ap- 
parent addition of any ferment : thus wine, beer, milk, etc., when allowed 
simply to stand exposed to the air, become sour, or otherwise decompose. 
These changes are, however, not effected without the presence of vegetable 
or animal life, and are true fermentations ; the sporules, or seeds of these 
living bodies, always float about in the air, and on dropping into the liquid 
begin to propagate themselves, and in the act of growing evolve the prod- 
ucts of the fermentation. If the above liquids be left only in contact with 
air which has been passed through a red-hot platinum tube, and thus the 
living sporules destroyed ; or if the air be simply filtered by passing through 
cotton wool, and the sporules prevented from coming into the liquid, it is 
found that these fermentable liquids may be preserved for any length of 
time without undergoing the slightest change."— Rose oe. 

t There are also other forms of fermentation, as the lactic, yielding 
lactic acid— the acid of sour milk ; butyric, yielding butyric acid, etc. 



196 ORGANIC CHEMISTRY. 

the first immediately, if not checked, and the alcohol 
is broken up into acetic acid and water ; thus, C 2 H 6 + 
2 (from the air) = C 2 H 4 2 + H 2 0. 

Yeast is the ferment which causes alcoholic fer- 
mentation. It consists of microscopic plants (Saccha- 
romyces cerevisice), which increase by the formation 
of multitudes of tiny cells not more than -^uo of an 
inch in diameter. In the brewing of beer they grow 
in great abundance, making common brewer's yeast.* 

Malt. — In making malt, the barley is thoroughly 
soaked in water, and then spread on the floor of a 
dark room, to heat and sprout. Here a curious 
change ensues, identical with that which takes place 
in every planted seed. Each one contains starch and 
a nitrogenous substance called gluten. The tiny 
plant not being able to support itself in the begin- 
ning, has here a little patrimony with which to start 
in life ; but, as the starch is insoluble in the sap, it 
must first be changed to a soluble form. We see, 
therefore, the need of a ferment ; but it would not 
answer to store up in the seed an active ferment, as 
that might cause a change before the plant was 
ready to grow, and thus the plant's capital be 
wasted. The gluten acts, therefore, as a latent fer- 
ment. As soon as the seed is planted it absorbs 
moisture from the ground, is turned into diastase — 
an active ferment f — the starch is converted into 

* The yeast-cakes of the kitchen are formed by exposing moistened In- 
dian meal, containing a ferment, to a moderate temperature, until the 
gluten or albuminous matter of the cake has undergone this alcoholic fer- 
mentation. They are then laid aside for use. 

t " Malt does not contain more than -Jo of its weight of diastase ; one 






FERMENTATION. 197 

dextrin and sugar, dissolved, and immediately ap- 
plied to the uses of the growing plant. This change 
takes place in the malting-room. The barley sprouts, 
and a part of its starch is turned to sugar, so as to 
give it a sweetish taste. If this germination were 
allowed to proceed, the little barley sprout would turn 
the sugar into woody fiber. To prevent this, the 
grain is heated in a kiln until the germ is destroyed. 
Barley in this condition is called malt, and is then 
transported to the breweries. 

Brewing Beer. — The malt is crushed and digested 
in water, to convert the remaining starch into dex- 
trin and sugar. Hops and yeast are added, and 
fermentation immediately commences. Bubbles of 
gas rise to the top with a low hissing sound, yeast 
gathers in a foamy cream that comes to the surface 
of the tub, while the alcohol gradually accumulates 
in the liquid. The beer is now drawn off into tight 
casks, where it undergoes a second fermentation ; 
the flavor ripens, and the C0 2 collecting, gives to the 
liquor, when drawn, its sparkling, foamy appearance. 

Lager Beer (Lagern, to lie) is so called because 
it is allowed to lie for months in a cool cellar, where 
it ripens very gradually. It is also fermented much 
more slowly and perfectly than ale or porter. 

Wine is made from the juice of the grape. The 
juice, or must, as it is called, is placed in vats, in the 
cellar, where the low temperature produces a slow 
fermentation. When all the sugar is converted into 

part of this substance being sufficient to change 2,000 parts of starch into 
dextrin and sugar."— Persoz and Pa yen. 



198 ORGANIC CHEMISTRY. 

alcohol and C0 2 , a dry wine remains ; when the fer- 
mentation is checked, a sweet wine is the result ; and 
when bottled while the change is still going on, a 
brisk, effervescing wine, like champagne, is formed. 
The flavor or " bouquet " of wine is due to the slow 
formation of a fragrant and aromatic ether.* (See 
p. 206). The tartaric acid of the grape gradually 
separates and collects on the sides and bottoms of 
the casks in an incrustation — tartar, an impure acid 
potassium tartrate, from which tartaric acid and 
cream of tartar are made. 

Alcohol in Beer, Wine, etc. — Alcohol is the intoxi- 
cating principle of all varieties of liquors, ale, beer, 
wine, cider, and the domestic wines. Ale and porter 
contain from 6 to 8 per cent, of alcohol ; wine varies 
from 7 per cent, in the light claret to 17 per cent, 
in the strong Port and Madeira ; brandy and whiskey 
have from 40 to 50 per cent. 

Ardent Spirits. — When any fermented liquor is 
distilled, the alcohol passes over, together with water 
and some fragrant substances which are condensed. 
In this way brandy is made from wine ; rum, from 
fermented molasses or cane-juice ; whiskey, from fer- 
mented corn, rye, or potatoes ; and gin, from 
fermented barley and rye, afterward redistilled with 
juniper-berries. The accompanying cut represents an 
apparatus used for this distillation. A is the boiler, 
B the dome, C a tube passing into 8, the condenser, 
where it is twisted into a spiral form called the 

* CEnanthic ether, a liquid with, a powerful odor, which causes the 
peculiar smell of grape- wine. 



FERMENTATION. 



199 



worm, in which the vapor from the boiler is con- 
densed, and drops out at D. (See " Physics," page 

188.) 



Fig. 69. 




a sm. 

Amyl Alcohol, C 5 H,,OH, is the chief constituent of 
" fusel oil," found in whiskey distilled from pota- 
toes. It is often present in common alcohol, giving 
a slightly unpleasant odor when it evaporates from 
the hand. It is extremely poisonous, and as it is 
often contained in liquors, must greatly increase 
their destructive and intoxicating properties. 

Besides these alcohols which have been described, 
and others which, like them, contain but one hy- 
droxyl group, there are alcohols which have two, 
three, and more OH groups. Among these the most 
important one is glycerin, C 3 H 5 (OH) 3 , which is a con- 
stituent of fats, and will be treated later (page 206). 



200 ORGANIC CHEMISTRY. 



THE ALDEHYDES AND ACIDS. 

When alcohols are oxidized they are converted 
into acids. By taking proper precautions, inter- 
mediate products, called aldehydes (alcohol dehydro- 
genatum), can be obtained from alcohols like those 
we have considered. The two stages of the oxidation 
are shown by the following equations : 

CH 3 -CH 2 0H + = H 2 + CH3-COH. 
CH3-COH + = CH3-COOH. 

The group ~-C = O.H is characteristic of the alde- 
hydes ; the group — C=O.OH, " the carboxyl group" 
of the organic acids. 

Ethyl Aldehyde, CH 3 — COH, is a colorless liquid 
boiling at 2 1 ° C. It is readily oxidized to acetic 
acid or reduced to ethyl alcohol. It has a peculiar 
and characteristic odor, which may be obtained by 
holding a red-hot coil of Pt wire in a goblet contain- 
ing a few drops of alcohol. 

Formic Acid, CH 2 2 or HC=O.OH, occurs in red 
ants (formica rufa) and stinging nettles, and can be 
obtained from them by distillation with water. It is 
best prepared by heating oxalic acid with glycerin.* 
It is a fiery, pungent liquid, which blisters the skin. 
It is a monobasic acid (page 112), the H of the car- 
boxyl group being alone replaceable by metals, and 
yields salts called formates, e. g. H — C=O.OK, potas- 
sium formate. 

* It can also be made by the oxidation of methyl alcohol, CH 3 OH. 




THE ALDEHYDES AND ACIDS. 201 

Acetic Acid, C 2 H 4 2 , or CH 3 — C=O.OH (acetum, 
vinegar), forms from two to four per cent, of com- 
mon vinegar, whence its name. The strongest acetic 
acid is known as the glacial, since it crystallizes into 
an ice-like solid at 17° C. It has an 

Eig. 70. 

aromatic taste and pungent odor, and, 
after a time, blisters the skin. 

Preparation. — Vinegar is made on a 
large scale by allowing a weak alcohol 
to trickle slowly through a cask filled 
with beech shavings, which have been 
soaked in vinegar. As the alcohol 
passes down, it is oxidized, and after 
two or three repetitions of the process, it becomes 
entirely converted into acetic acid * (vinegar). 

Older Vinegar. — By the alcoholic fermentation, 
sweet cider becomes "old cider T By exposure to the 
air the alcohol passes on to the second stage, and the 
acetic acid formed produces the sour taste of the 
vinegar. 

Pyroligneous Acid, wood-vinegar (see p. 192, note), 
is crude acetic acid. It is used in making acetates, 
from which the pure acid is obtained by the action 
of a stronger acid, as H 2 S0 4 . 

Properties. — Acetic acid is monobasic. One of its 
most important salts is " sugar of lead" (CH 3 — C = 
0.0) 2 Pb (see p. 164). Vinegars of commerce are 

* The oxidation of alcohol into acetic acid is due to a microscopic organ- 
ism (mycoderma aceti), which is called "mother of vinegar." It conveys O 
from the air to the alcohol. In the " quick- vinegar process " described, the 
organism is deposited on tshe shavings from the vinegar with which they 
are soaked. 



202 ORGANIC CHEMISTRY. 

often sharpened by the addition of H 2 S0 4 and pun- 
gent spices.* 

Its sole use as a food is as a condiment. It allays 
thirst, and was anciently carried by the Roman 
soldiers in a little flask for that purpose. Sugar 
added to vinegar quickly passes to the second stage 
of fermentation, and increases its strength. Indeed, 
vinegar is sometimes made entirely from sweetened 
water and tea-leaves, which act as a ferment. It pre- 
vents the decomposition of both animal and vegeta- 
ble substances, and is hence used for preserving them. 

Preserves frequently " work," as it is called, and 
then sour. The bubbles of gas which rise to the 
surface indicate the alcoholic fermentation. If 
neglected, this soon passes to the acetic stage. It 
may be checked by scalding, which destroys the fer- 
ment. 

Of the other acids of this series containing one 
carboxyl group, the only ones of especial interest 
are Palmitic acid C, 5 H 3l C0.0H, and Stearic acid 
C, 7 H 35 C0.0H, which, in combination with glycerin, 
form the common solid fats. Another related acid, 
the Oleic, is a constituent of the liquid fats (see 
p. 206). The so-called " stearin" candles are made 
of a mixture of palmitic and stearic acids. 

* We can easily detect these by evaporating a half -gill in a saucer, 
placed over hot water. As it boils down, add a little sugar, taking care not 
to allow it to burn. If the liquid turns black, it is proof of the presence of 
H 2 S0 4 . As the last evaporates, the odor of cayenne pepper, etc. (if there 
be any), can be readily distinguished. In England, commercial vinegar is 
permitted by law to have one part in % thousand of oil of vitriol, as this 
keeps it from molding. 



THE ALDEHYDES AND ACIDS. 203 

A few important acids, which may be regarded as 
derivatives of the paraffine series, and which contain 
two or more carboxyl groups, are treated below. 

Oxalic Acid, C 2 H 2 4 (C=0.0H) 2 , is familiar in the 
sour taste of rhubarb, sorrel, etc. In these plants 
the acid is combined with K and Ca. It may be pre- 
pared by the action of HN0 3 on sugar.* It is a 
potent poison. The antidote is powdered magnesia, 
or chalk, stirred in H 2 0. It is a test of lime, forming 
a delicate white precipitate of calcium oxalate. A 
solution of oxalic acid is much used to remove ink 
stains, and is often sold for this purpose under the 
deceptive name of "salts of lemon." The acid unites 
with the Fe of the ink, and the iron oxalate thus 
made is soluble in H 2 0. It should be washed out 
immediately, as it will corrode the cloth. 

CH(OH)CO.OH\ 

Malic Acid (C 4 H 6 5 , i ), occurs abun- 

'CH 2 CO.OH /' 

dantly in most acid fruits, particularly in unripe ap- 
ples, whence its name from malum, an apple. Citric 
acid, C 3 H 4 (0H) (CO.OH) 3 {citrus, a lemon), the acid of 
the lemon, lime, etc., is often found associated with 
it, as in the gooseberry, raspberry, and strawberry. 
Citric acid is used in medicine as magnesium citrate. 

_ CH(OH)CO.OH\ 

Tartaric Acid (C 4 H 6 6 , I J, exists in 

CH(OH) CO.OH/' 

* Oxalic acid is made on a large scale from sawdust, soda, and caustic 
potash. The woody fiber is resolved into oxalic acid, which combines with 
the bases, forming sodium and potassium oxalates. From these the acid is 
readily obtained. Sawdust will yield more than half its weight of crystals 
of this salt. 



204 ORGANIC CHEMISTRY. 

many fruits, principally in the grape, combined with 
K as acid potassium tartrate ("bitartrate of potash"). 
This settles during the fermentation of wine (see p. 
198), and when purified is called cream of tartar, 
from which the acid is prepared. It forms trans- 
parent crystals of a pleasant acid taste, which are 
permanent in the air. Its aqueous solution gradually 
becomes moldy, and spoils. Tartar emetic is an 
antimony potassium tartrate. Bochelle salt is a so- 
dium potassium tartrate ; it is commonly used in 
medicine in the form of Seidlitz powders. These are 
contained in a blue and a white paper. The former 
holds 120 grains of Rochelle salt, and 40 grains of 
bicarbonate of soda ; the latter, 3 5 grains of tartaric 
acid. They are dissolved in separate goblets. The 
one containing the acid is emptied into the other, 
when the C0 2 is set free, producing a violent effer- 
vescence, and disguising the taste of the medicine. 



THE ETHERS AND ETHEREAL 

SA LTS. 

The ethers are oxides of the organic radicals. 
They are thus analogous to the metallic oxides, just 
as the alcohols are to the metallic hydroxides, and 
are related to the alcohols in the same way that K 2 
is related to KOH. Each of the alcohols has its cor- 
responding ether. Thus we find : 

Methyl ether (CH 3 ) q O, corresponding to methyl alcohol, CH 3 OH. 
Ethyl ether (C 2 H s ) 2 0, corresponding to ethyl alcohol, C 2 H 5 OH. 
Propyl ether (C 3 H 7 ) 2 0, corresponding to propyl alcohol, C 3 H 7 OH. 
Etc., etc. 



THE ETHERS AND ETHEREAL SALTS. 205 

Such ethers as these, in which two radicals of the 
same kind are united with 0, are called simple 
ethers. It is easy to make ethers which contain dif- 
ferent radicals, as, for instance, CH 3 — — C 2 H 5 ; and 
in such cases they are called mixed ethers. 

Ethyl Ether (C 2 H 5 ) 2 0, Common or "Sulphuric" 
Ether* is made by heating a mixture of common 
alcohol and H 2 S0 4 . It is a colorless, very volatile 
liquid of a peculiar odor. It is much lighter than 
water, and somewhat soluble in it. Ether boils at 
35° C. Its vapor is thirty-seven times heavier than 
hydrogen, and can be poured like C0 2 . It is very in- 
flammable, and its vapor, with air, forms an explosive 
mixture. f Ether is a valuable ana3sthetic, and is ex- 
tensively used in surgery. 

Ethereal Salts are salts in which an organic radi- 
cal occupies the place of the metal in an ordinary 
salt. Thus, in making ether from alcohol by the ac- 
tion of H 2 S0 4 , there is first formed 2 m 5 S0 4 , in 

which the radical C 2 H 5 has replaced a H atom of the 
acid; it is analogous to KHS0 4 , which is formed by 
the action of H 2 S0 4 on KOH : 

KOH + H 2 S0 4 = H 2 + KHS0 4 . 
C 2 H 5 0H + H 2 S0 4 = H 2 + (C 2 H 5 )HS0 4 . 

As other examples of ethereal salts, or compound 
ethers, as they are often termed, we have : Ethyl 
sulphate (C 2 H 5 ) 2 S0 4 (analogous to K 2 S0 4 ); ethyl ni- 

* This name was given to it because H 2 S0 4 is used in its manufacture, 
and not because it contains any S. 

t Never use ether in the neighborhood of flames. 



206 ORGANIC CHEMISTRY. 

trate, C 2 H 5 N0 3 ; ethyl chloride, C 2 H 5 C1; ethyl acetate, 
CH 3 -C0.0C 2 H 5 . 

A number of ethereal salts are extensively sold as 
flavoring extracts for the use of confectioners and 
cooks. The essence of jargonelle pear is an alcoholic 
solution of amyl acetate ; apple oil, of amyl valerian- 
ate ; pine-apple, of ethyl butyrate. 

To this same class of compounds belong also the 
natural fats, most of which are mixtures of the 
ethereal salts which glycerin forms with palmitic, 
stearic, and oleic acids, and which are called palmitin, 
stearin, and olein. Butter consists of the glycerin 
salts of seven acids, all derivatives of the paraffine 
series. 

The Fats and Glycerin. — Palmitin and Stearin 
are solids, while olein is liquid. Therefore, the larger 
the proportion of olein which a fat contains, the 
lower its melting point, and the softer it is. Fats 
especially rich in palmitin are human fat and palm 
oil ; in stearin, mutton tallow, beef tallow, and lard ; 
in olein, sperm-oil, and codliver oil. 

Glycerin is an alcohol containing three OH groups, 
C 3 H(0H) 3 , and its ethereal salts, with the fatty acids, 
are: 

(CisHajCO.OJsCsIIs, glycerin tripalmitate or palmitin, 
(dyHasCO.OJgCaHs, glycerin tristearate or stearin, 
(CisHatCO.O^CaHs, glycerin trioleate or olein. 

Glycerin is obtained from the natural fats by heat- 
ing them with lime or lead oxide, or by the action of 
superheated steam. In the former cases, the calcium 
or lead salt of the acid is .formed, and the glycerin 



THE ETHERS AXD ETHEREAL SALTS. 207 

set free ; in the latter case, the fat is decomposed at 
once into acid and glycerin. The acids, when cool, 
are subjected to great pressure ; the oleic flows out. 
leaving the stearic and palmitic acids as a milk- 
white, odorless, tasteless solid, which is commonly 
called stearin, and extensively used in the manufact- 
ure of stearin or adamantine candles* 

Glycerin is an odorless, transparent syrup. It is 
soluble in H 2 and alcohol. On account of its heal- 
ing properties, its use is common in dressing wounds, 
insect bites, chapped hands, etc. 

By the action of HN0 3 and H 2 S0 4 , glycerin is con- 
verted into nitroglycerin (C 3 H 5 (N0 3 ) 3 , glycerin ni- 
trate, a compound ether), an oil that often explodes 
with fearful violence by a slight concussion. Dyna- 
m ite, used in blasting, is powdered silex, or infusorial 
earth (" Geology,' 7 p. 48), saturated with nitro-glycerin. 

Soap. — If sweet-oil and H 2 be placed in a test- 
tube and shaken, they will mix, but not unite : for 
on standing, the oil will rise to the top. Add. how- 
ever, caustic potash or a little "lye" (see p. 12 9), 
when, on heating, a clear, soapy solution will be 

* Wax candles are manufactured by the following process : A large num- 
ber of cotton wicks are hung upon a revolving frame with projecting arms. 
The -wicks are fitted at the ends with metal tags to keep the wax from 
covering that part. As the machine slowly turns, a man, standing ready 
with a vessel of melted wax. carefully pours a little upon each wick in 
succession. This process is repeated until the candles reach the desired 
size. They are then rolled on a smooth stone slab, the tops cut by conical 
tubes, and the bottoms trimmed, when they are ready for use. The large 
tapers burned in Catholic cathedrals are made by placing the wick on a 
sheet of wax, rolling it up till the right thickness is reached, when the 
candle is trimmed and polished as before. Spermaceti candles are run from 
the white, crystalline, solid fat which is found with sperm-oil in the head 
of the sperm-whale. 



208 ORGANIC CHEMISTRY. 

formed. The K of the alkali has combined with the 
oleic and palmitic acids of the oil, making two new 
salts — potassium oleate and potassium palmitate ; 
while the expelled glycerin remains floating in the 
liquid. 

The manufacture of soap is based on this princi- 
ple.* A variation in the alkaline base and the fat 
or oil used, produces the different kinds of soap. 
Potash, on account of its affinity for H 2 0, forms soft- 
soap. Soda is not deliquescent,! and hence makes 
hard-soap \ Lard forms a softer soap than tallow. 
Castile soap is made from olive-oil and soda. Its 
mottled appearance is due to the coloring matter 
which is stirred through it while it is yet soft. 
Home-made soap is prepared by boiling " lye " and 
" grease." § As the latter contains such a variety of 
fatty substances, the soap generally consists of the 
three salts — potassium oleate, palmitate, and stearate. 
Yellow soap contains some resin in place of fat. 
Cocoanut-oil makes a soap which will dissolve in salt 
water, as it contains an excess of alkali. Soap-balls 
are made by dissolving soap in a very little water, 

* Saponification (sapo, soap ; facere, to make) is the process of separating 
the fatty acids and glycerin, and is so named even when no soap is formed. 
One method is as follows : Tallow or lard is boiled with lime, and thus 
made into a calcium soap. This is decomposed by H 2 S0 4 , forming cal- 
cium sulphate, which, being insoluble, sinks to the bottom, leaving the 
three acids of the fat floating upon the surface. 

t A deliquescent substance is one that dissolves in H 2 0, which it ab- 
sorbs from the air. 

X Soap is frequently adulterated with gypsum, lime, pipe-clay, or sodium 
silicate. These may be detected by dissolving a piece of the soap in dis- 
tilled water or alcohol, and noticing if there be any precipitate. 

§ The heat hastens the chemical change, which takes place more slowly 
in making what is known as "cold soap." 



HALOGEN DERIVATIVES OF PARAFFINES. 209 

and then working it with starch to a proper consist- 
ency to be shaped into balls. White toilet-soaps are 
made from lard and soda. The curdling of soap in 
hard water is caused by the formation of a calcium 
or a magnesium soap, which is insoluble in H 2 0, and 
floats on the top as a greasy scum.* 

The Cleansing Qualities of Soap. — There exudes 
constantly from the pores of the skin an oily per- 
spiration, and this, catching the floating dust, dries 
into a film which will not dissolve in H 2 0. The alkali 
of the soap combines with this oily substance, and 
makes a soluble soap. In addition, the alkali also 
dissolves the cuticle of the skin, and thus produces 
the " soapy feeling," as we term it, when we handle 

soap. 

*-♦* 

HALOGEN DERIVATIVES OF 
THE PARAFFINES. 

The halogens can be caused to replace one or more 
atoms of H in the paraffines, and many of their de- 
rivatives. A few only of the compounds thus formed 
are of practical importance. 

Chloroform, CHC1 3 , tri-chlor-methane, is prepared 
by distilling alcohol, C 2 H 5 0H, with chloride of lime. 
It is a colorless, heavy liquid of a sweetish taste and 
ethereal odor. It is scarcely soluble in water, and 
when shaken with it quickly settles out at the bot- 
tom. It should evaporate without any unpleasant 

* A soap made from lard, in water containing calcium carbonate, would 
undergo the following reaction : Potassium oleate + calcium carbonate = 
calcium oleate + potassium carbonate. 



210 ORGANIC CHEMISTRY. 

odor or residue. It boils at 62° 0. It is very useful 
as an anaesthetic, and is employed as a solvent of I, 
P, S, caoutchouc, fatty and resinous bodies. 

Iodoform, CHI 3 , made by bringing together so- 
dium carbonate, alcohol and iodine, is a solid. It 
forms small yellow crystals, which melt at 119° 0. 
It is used in surgery. 

Chloral, CC1 3 — CHO, tri-chlor-aldehyde, is formed 
by passing CI through absolute alcohol. It is an oily 
liquid which combines with H 2 0, making Chloral 
Hydrate, a white, crystalline substance, much used 
to induce sleep. Taken in proper quantities, it is 
entirely safe, and is exceedingly pleasant in its in- 
fluence. 



THE CARBOHYDRATES. 



STARCIJ, WOODY FIBER, AND SUG^R. 



Pig. 71. 



1. STARCH (C 6 H I0 5 ). 

Source. — Plants accumulate it, 1, in their roots, as 
the carrot, the turnip, etc.; 2, in subterranean stems, 
as the potato, of which it forms about 2 per cent. ; 

3, in the base of their 
leaves, as the onion ; 4, 
in the seed, as corn, of 
which it forms about 
65 per cent., the bean, 
the pea, etc. In all 
these it is stored up 
for the future growth 
of the plant. It is kept 
in its starch form (lest 
it dissolve in the first 
rain), and then turned 
to sugar only when the 
plant needs it in growing. (See p. 196.) Under the 
microscope, each vegetable is found to have its pecu- 
liar form of starch granule, so that in this way any 
adulteration is easily detected.* 




Potato Starch. 



* " The structure of the grains of starch is very beautifully displayed by 
placing some of them in contact with a drop of concentrated solution of 
zinc chloride (tinged with a little free iodine) on the field of the micro- 



212 



ORGANIC CHEMISTRY. 



Fig. 72. 



Preparation. — Starch is made from wheat, corn, po- 
tatoes, etc. The process 
is essentially the same in 
all. The potato, for ex- 
ample, is ground to a 
pulp, and then washed 
with cold water. The 
starch settles from this 
milky mass as a fine, 
white precipitate. 

Properties. — Starch is 
insoluble in cold water ; 
in hot, it absorbs H 2 0, 
swells, and the granules 
burst, forming a jelly-like liquid, used for starching. 
The swelling of rice, beans, etc., 
when cooked, is owing to this 
property. By heating to 400° 
when dry, starch undergoes a 
peculiar change into a substance 
known as dextrin,* used as a 
mucilage on envelopes and adhe- 
sive stamps, for making " fig- 
paste," and stiffening chintzes. The test of starch is 
I, which forms in solution the blue iodide of starch. 




Wheal Starch. 



Fig. 73. 




Bursting of Starch Granule. 



scope. No change takes place in the grannies nntil a little water is added. 
They then become of a deep bine color, and gradually expand ; at first, a 
frill-like plaited margin is developed aronnd the globules ; by degrees this 
opens out ; the plaits upon the globule may then be seen slowly unfolding, 
and may be traced in many cases into the wrinkles of the frill ; ultimately 
the granules swell up to twenty or thirty times their original bulk, and 
present the appearance of a flaccid sac. "—Busk. 

* Dextrin is isomeric with starch, but is not discolored by I. 



CELLULOSE. 213 

Sago is the starch from the pith of the palm-tree ; 
tapioca and arrow-root are made from the roots of 
South American marshy plants.* 

Gum is found in the juices of nearly all plants, 
and frequently exudes, as in the peach, plum, and 
cherry. It is soluble in water, but not in alcohol. 
Gum arabic, which flows in transparent tears from 
an acacia tree, is the purest form.f Mucilage, which 
occurs in gum tragacanth, linseed, quince-seed, etc., 
is a modification of gum, and is insoluble in H 2 0. It 
forms with it, however, a gelatinous liquid, which is 
exceedingly useful. 

Vegetable Jelly. — "A variety of gum called pec- 
tose exists in nearly all fruits and vegetables. It 
gives to them their hardness while green." — Fremy. 
In the process of ripening, or by heat, acids, etc., it 
is turned into pectin. We find this abundant in the 
thick juice which exudes from an apple while baking. 
In the making of jellies, pectose is converted into a 
mixture of pectosic and pectic acids. 



2. CELLULOSE (C 6 H (0 5 ). 

Sources. — If a thin slice of wood be examined 
under the microscope, it will be seen to consist of a 
fibrous substance incrusted and compacted with 



* Very many of the farinaceous preparations sold for the sick and in- 
valid, under high-sounding names, are simply wheat or corn starch. 

t It is a soluble salt, being composed of arabic acid (C12H22OH, Gelis), 
combined with K and Ca. 



214 OKGAJSTIC CHEMISTRY. 

woody matter. The former is called cellulin 
(C 6 H, 5 ).* It composes the cells of all plants, giving 
them strength and firmness, and is found even in 
delicate fruits, holding their luscious juices. It occurs 
in various modifications, in wood, nut-shells, and 
fruit-stones. In the heart of a tree, its cells are hard 
and dense ; in the outer part, they are soft and 
porous ; in elder-pith and cork, light and spongy ; in 
flax and cotton, long, pliable, and fibrous ; in the bran 
of wheat and corn, digestible. 

Secretion. — All vegetation consists of these simple 
cells. They seem alike to the eye, yet they have a 
very diverse power of secretion. The cell of the 
sugar-maple converts its sap into sugar ; the milk- 
weed, into a milky juice ; the caoutchouc, into rubber; 
the rhubarb-plant, into oxalic acid ; and the rose- 
petal, into the most delicate of perfumes. 

Cells are always true to themselves. There seems 
to be a law of God stamped on each one, so that 
when we cut a tiny bud from one tree and graft it 
into another, it remains consistent with itself. It de- 
velops into a limb, and years pass by. The few single 
cells become a myriad, yet they have not changed. 
The sap flows upward in the tree ; but at a certain 
point — a hidden threshold which no human eye can 
discern — it comes under a new and strange influence. 
Here it is transformed, and produces fruit and flowers, 
in accordance with another and different growth. 
Somehow, quince-juice is made into pears, locust- 

* It is probable that the molecule of woody fiber is some multiple of 
this formula, as C 18 H 30 0i5. 



CELLULOSE. 215 

juice blooms out into fragrant acacias, and sweet and 
sour apples hang upon the same limb. 

Uses. — These are wonderfully various. Woody 
fiber is woven into cloth, built into houses, twisted 
into rope, twine, and thread, made into paper, 
cut into fuel, carved into furniture. We eat it, 
wear it, walk on it, write on it, sit on it, print on 
it, pack our clothes in it, sleep in it, ride in it, and 
burn it. 

Paper is made from cotton, linen, straw, or any 
substance containing cellular tissue. The finest 
writing-paper is manufactured from linen rags. 
These are first " shredded" upon scythe-blades — i. e., 
the seams are ripped open, buttons cut off, and the 
dust shaken out. 2d. They are steamed in a solution 
of chloride of lime for ten or twelve hours, until they 
are thoroughly bleached. 3d. They are received by a 
machine that alternately lacerates them by a cylin- 
der set with razor-like blades, and washes them with 
pure, cold water for six hours, until they are reduced 
to a mass resembling rice and milk. 4th. This pulp 
receives a delicate blue tint from smalt* 5th. It is 
diluted with H 2 nearly to the consistency of milk, 
and strained to remove the waxed ends and knots of 
thread that cause the little lumps which catch our 
pen when we write rapidly on poor paper. 6th. It 
flows over an endless belt of wire-gauze, about thirty 
feet in length, through which the water steadily 
drips from the pulp, as it slowly passes along, gain- 
ing consistency and firmness. 7th. It comes to a 

* Powdered glass colored with, oxide of cobalt. 



216 ORGANIC CHEMISTRY. 

part of the belt called the " dandy-roll," consisting of 
a cylinder, on the surface of which are wires arranged 
in parallel rows, or fancy letters, which print upon 
the moist paper a design — constituting what is 
termed "laid," or "wire-woven," paper. 8th. The 
paper, very soft and moist as yet, passes between 
rollers that squeeze out the water ; then between 
others which are hot, and dry it. 9th. It comes to a 
vat of sizing, composed of glue and alum, into which 
it plunges, and at the opposite side emerges only to 
go between other rollers, that press and dry it, at the 
end of which it passes under a cylinder set with 
knives, that clip the roll into sheets of any desired 
size. 

Paper Parchment is prepared by plunging unsized 
paper for a few seconds in H 2 S0 4 , of a specified 
strength, then washing off the acid. This, in some 
unknown way, changes its appearance and character, 
so that it resembles parchment, while its toughness 
is five times that of the paper from which it was 
made. 

Linen is made from the inner bark of flax. The 
plant is first pulled from the ground, to preserve the 
entire length of the stalk; next "rotted," by exposure 
to air and moisture, when the decayed outer bark is 
removed by "breaking"; then, by " hatcheling," the 
long, fine fibers are divided into shreds, and laid 
parallel, while the tangled ones are separated as 
"tow." It is then bleached on the grass, which 
renders the gray coloring-matter soluble by boiling 
in lye. The whitened flax is lastly woven into cloth. 



SUGAR. 217 

Cotton consists of the beautiful hollow, white hairs 
arranged around the seed of the cotton-plant. As 
it is always pure and white — except Xankin cotton, 
which is yellow — it would require no bleaching did 
it not become soiled in the process of spinning, etc. 

Gun-Cotton. — Pyroxylin (jmr, fire, and xulon,woo&) 
is prepared by dipping cellular tissue — cotton, saw- 
dust, printing-paper, etc. — in a mixture of HN0 3 and 
H 2 S0 4 of a certain specific gravity. It is then care- 
fully washed and dried. It is not materially changed 
in appearance, but a part of its H has been replaced 
by N0 2 , and it has become very inflammable. It 
burns very rapidly, and, unlike gunpowder, leaves no 
residue. It explodes on percussion with a force which 
is far greater than that of gunpowder. A mixture 
of gun-cotton and camphor is widely used under the 
name of celluloid.. 

Collodion is a solution of gun-cotton in ether and 
alcohol. It forms a syrupy liquid, which is much 
used by photographers. 



3. SUGAR. 

Cane-Sugar (C l2 H 22 l ,),* Sucrose, is obtained from 
the sap of the sugar-maple, and the juice of the 
sugar-cane, sorghum, and beet. In making it from 

* A very brilliant experiment showing the presence of C in Ci 2 HooOn 
is obtained by putting on a clean, white plate, a mixture of finely-pulver- 
ized white sugar and KC10 3 . Upon adding a few drops of H 2 S0 4 , a vivid 
combustion will ensue. By mixing with the sugar a few iron and steel 
filings, and performing the experiment in a dark room, or out-of-doors at 
night, fiery rosettes will flash through a rose-colored flame, and produce a 
fine effect. 



218 ORGANIC CHEMISTRY. 

the sugar-cane, the canes are crushed between iron 
cylinders, to express the juice. A little lime is added 
to neutralize the acids, which would prevent com- 
plete crystallization of the sugar, and to remove 
certain substances which would cause fermentation, 
and it is then evaporated to a thick jelly, and set 
aside to cool. The sugar crystallizes readily, forming 
brown sugar, which is put in perforated casks to drain. 
The drainings, or " mother-liquor," constitute molasses. 

Refining. — Brown sugar is dissolved in H 2 0, filtered 
through twilled cotton to remove the coarse impuri- 
ties, and then through a deep layer of animal char- 
coal. The colorless solution is next evaporated in 
vacuum pans, from which the air is exhausted, so 
that the sugar boils at so low a temperature as to 
avoid all danger of burning. When sufficiently con- 
centrated, the liquid is removed and set aside to 
crystallize. If the mass of crystals is dried in 
molds, it forms loaf-sugar; if in centrifugal ma- 
chines, granulated sugar* The drainings constitute 
"syrup," " sugar-house molasses," etc. 

Confectionery. — Terra alba (white earth) is im- 
ported from Ireland for use in lozenges, drops, etc.f 

* This apparatus consists of a cylindrical drum mounted upon a vertical 
axis, to which, a rapid rotary movement can be given. The outer side of 
this drum is made of a stout but closely-woven net- work. The drum is 
inclosed in a large, fixed, cylindrical vessel, capable of holding the liquid 
which may pass out through the net-work. A charge of sugar is placed in 
the inner drum, which is then made to revolve rapidly. The syrup escapes 
through the wire-gauze into the outer drum, while the crystals are rapidly 
dried. 

t We can, and should, test all the candy we purchase by putting a small 
piece in a glass of water. Whatever settles to the bottom and remains un- 
dissolved is an adulteration. 



SUGAR. 219 

Confectionery is often colored by dangerous poisons, 
so that prudence forbids the use of any colored 
candy. Licorice drops are frequently only the poor- 
est brown sugar, terra alba, and a flavoring of licorice 
to make the unwholesome mixture palatable. Gum- 
drops are made, not from gum arabic, but generally 
of a species of glue manufactured out of hoofs, 
parings of hides, etc. However repugnant it may 
appear, this substance is perfectly clean and whole- 
some. Rock candy is formed by suspending threads 
in a strong solution of sugar. It crystallizes upon 
the rough surface in large, six-sided prisms. 

Caramel, familiarly called burnt sugar, is formed 
whenever sugar is heated above its melting point, 
as when sweetmeats boil over on the stove ; H 2 is 
lost, and C remains in excess. It is used by confec- 
tioners and for coloring liquors. 

Grape -Sugar (C 6 H l2 6 ), Dextrose, is found in 
honey, figs, and many kinds of fruit. Its sweeten- 
ing power is about three fifths that of cane-sugar. 

Sugar from Starch. — The difference in the con- 
stitution of starch and grape-sugar is only H 2 0. By 
boiling corn or potato-starch with dilute H 2 S0 4 , it is 
transformed into dextrose. The solution, evaporated 
to a syrup, is known commercially as "glucose," 
" mixing syrup," etc. When evaporated to dryness, 
the product is known as " grape-sugar."* 

* Saw-dust, paper, and even rags, can in the same way be converted 
into sugar. Indeed, Professor Pepper speaks of seeing some made out of an 
old shirt. Wonderful beyond our comprehension is that chemical force 
which can transform a cast-off garment into a substance which will delight 
the palate. (The transformation of rags into paper is not a chemical one.) 



220 ORGANIC CHEMISTRY. 

" Candied Jellies, Preserves, Etc. 1 ' — The sugar of 
many kinds of ripe fruits consists of grape or cane 
sugar, mixed with fruit-sugar. The latter changes 
gradually into grape-sugar and crystallizes, as in 
honey, dried figs, etc.* 



Necessity of Organization. — We have found many 
elements which are necessary to the growth of our 
bodies, but still we can not live upon them. We need 
phosphorus, but we can not eat it, for it is a deadly 
poison. We need Fe, but it would make a most un- 
savory diet. We need CaO, but it would corrode our 
flesh. We need H, but it must be combined with 0, 
as in H 2 0, to be of any value to us. We need C, but 
charcoal would form a very indigestible food. If we 
were shut up in a room with all the elements of 
nature, we not only could not combine them so as 
to produce those organic substances necessary to our 
life and comfort, but we should actually die of starva- 
tion. We thus find that the mineral matter must be 
organized before we can use it to advantage. 

Plants Organize Matter. — We have seen that in 
the plant the sunbeam decomposes C0 2 , and returns 
to the air the life-giving ; that we can not create 
energy ourselves, or draw it direct from the sun, 

Thus the chemist faintly imitates nature, which, ever out of waste and 
refuse, springs afresh. The fair petals of the lily rest upon the black mud 
of the swamp, and the products of decay come back to us in objects of use 
and forms of beauty. 

* Fruit-sugar is isomeric with grape-sugar, but is much sweeter. The 
latter, as it is noted for its right-handed rotation of the plane of polarized 
light, is called dextrose (dextra, right), and the former, from its left-handed 
rotation, laevulose {Icevus, left). (See "Physics," p. 170.) 



THE AROMATIC COMPOUNDS. 221 

but must take that which the plant has hoarded 
for us. We shall now find that, in addition, the plant 
changes inorganic matter to organic. It takes up the 
elements we need for our growth and for use in the 
arts, and combines them into plant-products, such as 
wood, starch, sugar, etc. We are thus dependent 
upon the vegetable world for the grand staples of 
commerce and of luxury — all that we eat, drink or 
wear. Each tiny leaf, every tree and shrub, every 
spire of grass even, is working constantly for us. The 
earth was once a burnt body — the cinders of the vast 
fire amid which it had its origin. (See " Geology," 
p. 17.) Every organized substance now on its sur- 
face has been rescued from the grasp of by the 
plants. 



THE AROMATIC COMPOUNDS. 

The name of this large and important group of 
compounds is due to the fact that many of its mem- 
bers occur in balsams, resins and essential oils which 
have an aromatic odor. The simplest aromatic hydro- 
carbon is benzol, or benzene, C 6 H 6 , and the other 
hydrocarbons and compounds of the group are de- 
rivatives of this, formed by the replacement of its H 
by elements or groups. 

Benzene, C 6 H 6 , is a product of the distillation of 
coal-tar, obtained in gas-making (see p. 72). It is a 
colorless oil, which is a good solvent for gutta- 
percha, caoutchouc, and fats. It is lighter than 



222 ORGANIC CHEMISTRY. 

water, boils at 80.5° C, and is chiefly used for the 
preparation of its derivatives, many of which are of 
the greatest importance. 

Nitro- Benzene, C 6 H 5 N0 2 , is made by the action of 
nitric acid on benzene. It is a heavy, oily liquid, 
with an odor like that of bitter almonds. It is some- 
times called essence of mirbane, and is used in 
scenting soap and in perfumery, but is chiefly valu- 
able as the source of aniline, from which are prepared 
the celebrated coal-tar dyes. — Example: Mauve, ma- 
genta, etc. Who but a chemist would have searched 
in black, sticky coal-tar for these rainbow-tints, the 
stored-up sunshine of the carboniferous age ! 

Aniline, C 6 H 5 NH 2 , is formed by the action of 
nascent H on nitro-benzene. On a large scale, it is 
made by mixing the nitro-benzene with iron filings 
and HC1. It is a colorless liquid, which becomes 
rapidly colored on exposure to the air. It is a strong 
base, uniting with nearly all acids to form crystal- 
line salts. In this characteristic it resembles ammo- 
nia, NH 3 , and it may be looked upon as ammonia in 
which an H atom has been replaced by the organic 
radical phenyl, C 6 H 5 . By treatment with oxidizing 
agents, aniline yields a great variety of derivatives, 
among them the exceedingly valuable aniline dyes.* 

* "In 1856, Mr. Perkin, while experimenting with aniline in hopes of 
making quinine, treated it with potassium bichromate. He did not suc- 
ceed in his attempt, but he obtained a beautiful purple dye, which was soon 
introduced to commerce under the name of mauve. A host of imitators at 
once sought to obtain the color without using potassium bichromate. As 
the only use of the latter was to oxidize the aniline, they reasoned that 
they might use any other oxidizing agent. Arsenic, among other substances, 
was tried, but, instead of a purple, the red known as magenta was the result. 



THE AROMATIC COMPOUNDS. 223 

Aniline was discovered in 1826, among the products 
of the dry distillation of indigo, and received its 
name from anil, the Portuguese term for indigo. 
Phenol, C 6 H 5 OH, Carbolic Acid* is noted for its 



The coloring matter, however, does not contain any arsenic ; being a salt 
of a base called rosaniline. Rosaniline itself is colorless, and reveals its 
magnificent tints only in its compounds. ' The crystals of its salts exhibit 
by reflected light the metallic green color of beetles' wings, but are of a 
deep red color when seen by transmitted light.' Magenta is manufactured 
on an enormous scale in England, more as a substance from which to 
obtain other dyes than for direct use in dyeing. A single firm produces 
twelve tons a week. The quantity of magenta furnished by one hundred 
pounds of coal is very small ; but this is compensated for by its intense 
coloring power, since it will dye a quantity of wool nearly equal in weight 
to the coal. In making magenta on the large scale, there are considerable 
quantities of residual products. These, of course, have been examined with 
a view to further profit, and the result has been the discovery of a beauti- 
ful orange color called phosphirw. This is much used to produce scarlet, by 
first dyeing the silk or wool with magenta, and then passing it through a 
bath of phosphine. By treating magenta with aniline, a beautiful blue is 
obtained. This is insoluble in water, but is rendered soluble exactly as in- 
digo is, by treating it with sulphuric acid. Another curious dye formed 
from aniline is known as Nicholson's blue. This is completely discolorized by 
alkalies, and the color is restored by acids. In dyeing with it, the silk or 
wool is first immersed in a colorless solution of the dye, and then dipped 
into dilute sulphuric acid, when the blue is at once developed. If magenta 
is heated with iodide of ethyl or methyl, an excess of the iodide being em- 
ployed, a most beautiful green is the result. If, however, this green is 
heated sufficiently to drive off the excess of iodide, a violet color is the 
result; so that it will not do for ladies wearing dresses dyed with this 
green to sit too near the fire. After all the coloring matter has been ex- 
tracted from the aniline, a residue remains which has an intense black 
color, and is largely used for making printing-ink. Very few of the aniline 
colors, when in powder, give a person any idea of the color which they will 
produce when moistened. Magenta, for instance, when dry, is a beautiful 
green, with a bronze-like luster. It is a pretty experiment to coat a sheet 
of glass with one of these colors, which is readily done by dissolving in 
alcohol (Hofmann's violet being the best), and allowing a film of it to 
evaporate on the glass. "When seen by transmitted light it is of a beauti- 
ful violet, but with reflected light it displays a tint rivaling in brilliancy 
the tail of a peacock."— Boston Journal of Chemistry. 

* The acid may be considered as the hydroxide of the radical phenyl, 
and hence is sometimes called phenyl alcohol. 



224 ORGANIC CHEMISTRY. 

antiseptic and disinfecting properties. It is one of 
the products of coal-tar distillation, and forms white 
crystals. It is very poisonous. By heating it with 
HN0 3 , C 6 H 2 (N0 3 ) 3 0H, picric acid is formed. This 
colors a rich yellow, and is a very popular silk dye. 
It forms salts by the replacement of the H of the 
OH group, e.g. C 6 H 2 (N0 2 ) 3 .OK. The picrates are yel- 
low, explosive salts. Potassium picrate is used in 
making certain explosives. 

Among the other products obtained by distilling 
coal-tar are : Coal-tar Naphtha ; this is a volatile, 
limpid oil, with a peculiar odor, and generally a light 
straw color. It is composed of several hydrocarbons, 
and is very inflammable. Naphthalene is a crystalline 
solid occurring in beautiful pearly scales. It is 
especially abundant in dead-oil, and may be formed 
by passing olefiant gas or benzol through red-hot 
tubes. Anthracene accompanies naphthalene in the 
latter part of its distillation. It is also a white solid. 
It is of interest since the coloring principle of mad^ 
der — alizarine — has been made from it. Dead-oil is 
used for preserving timber ; as a cement for roofs 
and walls ; for oiling machinery, etc. 

The Acids of this group contain the carboxy] 
group —CO.OH, like the acids of the paraffine series, 
Among them are benzoic acid, C 6 H 5 CO.OH ; salicylic 
acid, C 6 H 4 (OH) CO.OH, both of which are used in 
medicine, the latter and its salts being especially im- 
portant. 

Benzoic Aldehyde, C 6 H 5 CHO, is the fragrant oil 
of bitter almonds, and methyl salicylate, C 6 H 4 (OH) 



THE TERPENES AND CAMPHORS. 225 

CO.OCH3 (an ethereal salt), is the natural oil of the 
wintergreen. 

Toluene, C 6 H 5 CH 3 (methyl benzene), is, next to 
benzene, the most important of the hydrocarbons of 
the aromatic group. Like benzene, it yields, when 
treated with nitric acid, a nitrocompound, nitro- 
toluene, C 6 H 4 N0 2 CH 3 , which is reduced by nascent H 
to toluidine, C 6 H 4 NH 2 CH 3 . Toluene is always present 
in commercial benzene, and hence common aniline 
contains some toluidine, which is of importance in 
the making of aniline dyes. 



THE TERPENES AND CAM- 
PHORS. 

The Volatile or Essential Oils. — The volatile oils, 
unlike the fixed, make no soaps, and dissolve readily 
in alcohol or ether. Their solution in alcohol forms 
an essence. 

Sources. — The volatile or essential oils are of 
vegetable origin. They are found in the petals of a 
flower, as the violet ; in the seed, as caraway ; in the 
leaves, as mint, or in the root, as sassafras. Some- 
times several kinds of oil are obtained from different 
parts of the same plant. — Example: In the orange 
tree, the flower, leaves, and rind of the fruit furnish 
each its own variety. The perfume of flowers is 
produced by these volatile oils ; but how slight a 
quantity is present may be inferred from the state- 



226 ORGANIC CHEMISTRY. 

ment that " one hundred pounds of fresh roses will 
give scarcely a quarter of an ounce of Attar of 
Roses." 

Preparation. — In the peppermint and many others, 
the plant is distilled with water. The oils pass over 
with the steam, and are condensed in a cooler con- 
nected with the "Mint Still." The oil floats on the 
surface of the condensed water, and may be re- 
moved. A small portion, however, remains mingled 
with the latter, which thus acquires its peculiar taste 
and odor, constituting what is termed a " perfumed 
water." In some flowers, as the violet, jasmine, etc., 
the perfume is too delicate to be collected in this 
manner. They are, therefore, laid between woolen 
cloths saturated with some fixed oil. This absorbs 
the essential oil, which is then dissolved by alcohol. 
The oil of lemon or orange is obtained from the 
rind of the fruit by expression, or by digesting in 
alcohol. 

Composition. — C, H, 6 is the common formula of a 
large number of these oils. Thus the oils of lemon, 
cloves, juniper, birch, black pepper, ginger, bergamot, 
turpentine, cubebs, oranges, etc., with many others, 
are isomeric. 

Oil of Turpentine (C, H I6 ), is a type of this group. 
It is made by distilling pitch. It is generally called 
spirits of turpentine. It is highly inflammable, and, 
owing to the excess of C, burns with a great smoke. 
Turpentine is used in making varnishes and in med- 
icine. By the union of two atoms of its H with an 
atom of the of the air, to form H 2 0, it is converted 



THE TERPENES AND CAMPHORS. 227 

into rosin.* Camphene is obtained by repeated dis- 
tillation of turpentine. Burning-fluid is a mixture of 
camphene and alcohol. In the heat of the burning 
H of the latter, the C of the former is consumed, 
and this produces a bright light. The tendency of 
camphene to smoke is thus diminished, and the 
illuminating power increased. By the action of HC1 
on turpentine or oil of lemons, an " artificial cam- 
phor" is produced, which much resembles common 
camphor. 

Camphor (C, o H, 6 0) is obtained by distilling chips 
of the camphor-tree and its roots with water, and 
condensing the vapors on rice-straw. It is purified 
by sublimation. When kept in a bottle, it vaporizes, 
and its delicate crystals collect on the side toward 
the light. Taken internally, except in small doses, it 
is a virulent poison. Its solution in alcohol is called 
"spirits of camphor." If H 2 be added to this, the 
camphor will be precipitated as a flour-like powder, f 

The Resins and Balsams. — The resins are gen- 
erally formed from the essential oils by a slow 
oxidation.— Example : Turpentine, as we have just 
seen, is changed to rosin, a resinous substance. If 
the resin is dissolved in some essential oil, it is 



* In this way, the turpentine around the nozzle of a bottle in which it 
is kept becomes first sticky, and then resinous. Old oil should not be taken 
to remove grease spots, as, while it will remove one, it will leave another 
of its own. 

t Though camphor-gum is powdered with difficulty, a few drops of 
alcohol will remove all trouble. When small particles of powdered camphor 
are thrown on water free from grease, each fragment begins to dissolve 
with a remarkable gyratory motion, which is instantly checked by a drop 
of an essential oil allowed to fall upon the surface of the liquid. 



228 ORGANIC CHEMISTRY. 

called a balsam. — Example: Pitch is a balsam, since 
by distillation it is separated into rosin and turpen- 
tine. They generally exude from incisions in trees 
and shrubs, in the form of a balsam, which oxidizes 
on exposure to the air, and becomes a resin. — Ex- 
ample : Spruce gum. The resins are translucent or 
transparent, brittle, insoluble in H 2 0, but soluble in 
ether, alcohol, or any volatile oil, and form varnishes. 
They are non-conductors of electricity, and burn with 
much smoke. They do not decay, and indeed, have 
the power of preserving other substances.* 

Rosin constitutes about 75 per cent, of pitch, a 
resinous substance which exudes from incisions made 
in the trunks of certain species of pine. It is used 
in making soaps, to increase friction in violin-bows 
and the cords of clock-weights, and in soldering. 

Lac exudes from the ficus-tree of the East Indies. 
An insect punctures the bark, and the juice flows 
out over the insect, which works it into cells in 
which to deposit its eggs. The dried gum incrusting 
the twigs is called stick-lac ; when removed from the 
wood, seed-lac; when melted and strained, shellac. 
The liquefied resin is dropped upon large leaves, and 
so cools in broad, thin pieces. Sealing-wax is made 
of shellac and Venice turpentine ; vermilion or red 
lead being added to give the red color. Shellac is 
much used in making varnishes. 

Gum Benzoin also exudes from a tree in the East 



* For this reason they were used in embalming the bodies of the ancient 
Egyptians, which, after the lapse of two thousand years, are yet found dried 
into mummies in their mammoth tombs— the Pyramids. 



THE TERPENES AND CAMPHORS. 229 

Indies. It is a source of benzoic acid. It is used in 
fumigation and in cosmetics, and on account of its 
fragrant odor is burnt as incense.* 

Amber is a fossil resin which has exuded in some 
past age of the world's history from trees now ex- 
tinct. It is sometimes found containing various 
insects perfectly preserved, which were without 
doubt entangled in the mass while it was yet soft. 
These are so beautifully embalmed in this trans- 
parent glass that they give us a good idea of the 
insect life of that age. Amber is cast up by the sea, 
principally along the shores of the Baltic ; although 
it is also found in beds of lignite. It is commonly 
translucent, and susceptible of a high polish. It is 
used for ornaments, mouth-pieces, necklaces, buttons, 
etc. ; and is an ingredient of some varnishes. 

Caoutchouc, or India-rubber, exudes from certain 
trees in South America as a milky juice, f The 
solvents of rubber are ether, naphtha, turpentine, 
chloroform, carbon disulphide, etc. It melts, but 
does not become solid on cooling. Freshly-cut sur- 

* Place some green sprigs under a glass receiver, and at the bottom a 
hot iron, on which sprinkle a little benzoic acid. It will sublime and 
collect in beautifully delicate crystals on the green leaves above, making a 
perfect illustration of winter frost-work. 

t The globules of rubber are suspended in it as butter is in milk. The 
tree, it is said, yields about a gill per day from each incision made. A 
little clay cup is placed underneath, from which the juice is collected and 
poured over clay or wooden patterns in successive layers as it dries. To 
hasten the process it is carried on over large open fires, the smoke of 
which gives to the rubber its black color ; when pure, it is almost white. 
When nearly hard, the rubber will receive any fanciful design which may 
be marked upon it with a pointed stick. The natives often form the clay 
into odd shapes, as bottles, images, etc., and the rubber is sometimes ex- 
ported in these uncouth forms. 



230 OKGAJSTIC CHEMISTRY. 

faces readily cohere ; this property, together with its 
power of resisting most re-agents, renders it invalu- 
able to the chemist in making flexible joints and 
tubes. " It loses its elastic power when stretched for 
a long time, but recovers it on being heated. In the 
manufacture of rubber goods for suspenders, etc., 
the rubber thread is drawn over bobbins, and left for 
some days until it becomes inelastic. In this state it 
is woven, after which a hot wheel is rolled over the 
cloth to restore the elasticity." 

Vulcanized Rubber is made by heating caout- 
chouc with a small amount of sulphur. This 
constituted Goodyear's original patent.* It is less 
liable to be hardened by cold, or softened by heat, 
and admits of many uses to which common rubber 
would be entirely unsuited. If sulphurized rubber 
be heated to a high temperature, it becomes a hard, 
brittle, black solid (vulcanite or ebonite), capable of 



* Mr. Q-oodyear had been experimenting to find some way of rendering 
rubber insensible to beat and cold. It is said that one day, while talking 
with a friend, he happened to drop a bit of S in a pot of melted rubber. 
By one of those happy intuitions which seem to come only to men of 
genius, he watched the process, and to his amazement found that, while 
the appearance of the rubber was the same— elastic, odorous, and tasteless- 
its stickiness was gone, and it had gained the properties he so much de- 
sired. He immediately took out a patent in this country, and sailed for 
England, where, instead of securing his secret by a similar patent, he 
offered to sell it for £10,000. Charles Hancock, with whom he had been 
corresponding for several years, and who had been engaged in similar ex- 
perimenting, resolved to discover it himself. He shut himself up in his 
laboratory, and went to work. Disheartening failures marked every at- 
tempt. At last he tried S. At first, he did not succeed ; but, persevering, 
he finally saw, amid the stifling fumes of brimstone, the soft rubber 
metamorphosed into the vulcanized caoutchouc. He, too, was possessed of 
the secret, and, taking out a patent, reaped the reward of his patient 
labor. 



THE ALKALOIDS. 231 

a high polish, which is used for knife-handles, combs, 
buttons, etc. 

Gutta-percha resembles caoutchouc in its source, 
preparation, and appearance. It softens in hot water, 
and can then be molded like wax. When cooled, it 
assumes its original solidity. It is extensively used 
in taking impressions of medals, etc. 



THE ALKALOIDS. 

The alkaloids, or organic bases, as they are called, 
are the bases of true salts found in many plants. 
They dissolve very slightly in H 2 0, but freely in 
alcohol. They are bitter in taste, generally have a 
powerful effect on the animal creation, and rank 
among the most dangerous poisons and valuable 
medicines. All the alkaloids contain N in addition 
to C and H, and many also contain 0. Some of the 
alkaloids have been obtained by artificial means in 
the laboratory. 

Opium is the dried juice of the poppy plant, which 
is extensively cultivated in Turkey for the sake of 
this product. Workmen pass along the rows soon 
after the flowers have fallen off, cutting slightly each 
capsule. From these incisions a milky juice exudes, 
and collects in little tears. These are gathered, and 
wrapped in leaves for the market. Opium contains 
some seventeen different alkaloids in combination 
with at least two acids. In small doses, opium is a 



232 ORGANIC CHEMISTRY. 

sedative medicine ; in larger ones, a narcotic poison. 
Laudanum is the tincture of opium ; and paregoric, 
a camphorated tincture flavored with aromatics. 

Opium -eating. — Opium produces a powerful in- 
fluence on the nervous system. It stimulates the 
brain and excites the imagination to a wonderful 
pitch of intensity. The dreams of the opium-eater 
are said to be vivid and fantastic beyond description. 
The dose must, however, be gradually increased to 
repeat the effect, and the result is most disastrous. 
The nervous system becomes deranged, and no relief 
can be secured save by a fresh resort to this baneful 
drug.* Labor becomes irksome, ordinary food dis- 
tasteful, and racking pains torment the body. 

Morphine {Morpheus, the god of sleep) is the 
chief narcotic principle of opium, and like it is used 
to alleviate pain and produce sleep. It is usually 
given as a sulphate or chloride. 

Quinine is prepared from Peruvian bark. A tinct- 

* In time, the whole system becomes so impregnated with it that even 
large additional doses fail to produce the delightful effect which at first so 
fascinated the victim. Then, while acting upon the nerves, it set free a 
vast amount of vitality and energy, but now it has satisfied itself. The 
subtle alkaloid has affected the tissues and coatings of the entire internal 
organism. If, resolutely, one summons his enfeebled will, and commences 
the conflict, an agony of endurance, which defies all description, is before 
him. The whole body must be reorganized. If, too weak to attempt so 
terrible a struggle, he continues the use of the fatal drug, he moves on 
directly to his fate— the opium-eater's grave. Paregoric, laudanum, mor- 
phine, and the different preparations of opium, are, in almost every case, 
taken first as a sedative from pain or fatiguing labor, with no thought 
of becoming addicted to their use. But so insinuating is it that the vic- 
tim forms the habit ere he is aware, and knows he is a slave only when 
he attempts to cease the customary dose. 3STo person can be too careful 
in beginning the use of a narcotic whose influence is liable to become so 
destructive. 



THE ALKALOIDS. 233 

ure of the ba,rk, or sulphate of quinia, is employed 
in medicine in cases of fever and ague, and other 
periodic diseases, and also as a tonic. 

Nicotine is the active principle of the tobacco 
plant, of which it forms from 2 to 8 per cent. It is 
volatile, and passes off in the smoke. A drop will kill 
a large dog. It probably produces many of the ill 
effects which follow the use of tobacco. 

Strychnine is prepared from the mix vomica and 
the St. Ignatius bean. It is also a constituent of the 
celebrated upas poison.* "It is so intensely bitter 
that one grain will impart a flavor to twenty-five 
gallons of water. One thirtieth of a grain has killed 
a dog in thirty seconds, while half a grain has been 
fatal to man." 

The Chromatic Test, as it is called, consists in 
placing on a clean porcelain plate a drop of the 
suspected liquid, a drop of H 2 S0 4 , and a crystal of 
potassium bichromate. Mix the three very slowly 
with a clean glass rod. If there be any strychnine 
present, it will change the color into a beautiful 
violet tint, passing into a pale rose.f 



* " The ' woorara, 1 with which the South American Indians poison their 
arrows, is allied to strychnine. This is so deadly that the scratch of a 
needle dipped in it will produce death ; yet it may be swallowed with im- 
punity. 11 — Miller. 

t Strychnine is the only poison, except brucine (and that also is ex- 
tracted from nux vomica), that produces tetanus, or lock-jaw. This symp- 
tom proves to the physician that death has been caused by this alkaloid. 
To exhibit the effect of the poison a frog is sometimes brought into a court- 
room, and made to show its action. So sensitive is this little animal that if 
the sixteen-thousandth of a grain of strychnine be introduced into its lungs, 
the drug will render it violently tetanic in about ten minutes. 



234 ORGANIC CHEMISTRY. 

Caffeine and Theine constitute the active prin- 
ciple of tea* and coffee, f and are identical. They 
crystallize in long, flexible, silky needles. In addi- 
tion, tea contains from 13 to 18 per cent, of a 
form of tannin, about 22 per cent, of extractive 
matter, some coloring substances, and a volatile oil 
which gives to it its aromatic odor and taste. Coffee 
contains about 14 per cent, of oil and fat, and also 
an essential oil which is developed in roasting, and is 
very volatile, so that it will soon escape unless the 
coffee be kept tightly covered. 



* Tea-raising.— Tea-plants resemble in some respects the low whortleberry 
bush. They are raised in rows, three to five in a hill, very much as corn is 
with us, but they are not allowed to grow over one and a half feet high. 
The medium-sized leaves are picked by hand, the largest ones being left to 
favor the growth of the bushes. Each little hill or clump will furnish from 
three to five ounces of green leaves, or about one ounce of tea, in the course 
of the season. The leaves are first wilted in the sun, then trodden in baskets 
by barefooted men to break the stems, next rolled by the hands into a spiral 
shape, then left in a heap to heat again, and finally dried for the market. 
This constitutes Black Tea, and the color would be produced in any leaves 
left thus to wilt and heat in heaps in the open air. The Chinese always 
drink this kind of tea. They use no milk or sugar, and prepare it, not by 
steeping, but by pouring hot water on the tea and allowing it to stand for 
a few minutes. Whenever a friend calls on a Chinaman, common politeness 
requires that a cup of tea be immediately offered him. 

Green Tea is prepared like black, except that it is not allowed to wilt or 
heat, and is quickly dried over a fire. It is also very frequently, if not 
always, colored— cheap black teas and leaves of other plants being added in 
large quantities. In this country, damaged teas and the " grounds " left at 
hotels are re-rolled, highly colored, packed in old tea-chests, and sent out 
as new teas. Certain varieties of black tea even receive a coating of black- 
lead to make them shiny. 

t Coffee is the seed of the coffee plant, a native of the tropics. The 
plant is very prolific, remaining in flower eight months of the year and 
usually producing three harvests annually. The fruit resembles the cherry, 
but contains two seeds or "beans" instead of a single stone, inclosed in a 
thick leathery skin. The drying of the coffee is a most important process. 
A. shower of rain will discolor the bean and depreciate its value. 



DYES AND DYEING. 235 



DYES AND DYEING. 

Many of the organic coloring principles are of 
vegetable origin. They are found in the roots, wood, 
bark, flowers, and seeds of plants. 

Dyeing. — Very few of the colors have such an 
affinity for the fibers of the cloth that they will not 
wash out. Those which, like indigo, will dye directly, 
are called substantive colors. But the majority are 
adjective colors, which require a third substance 
having an attraction for both the coloring matter 
and the cloth, to hold them together. Such sub- 
stances are called mordants {mordeo, to bite), because 
they bind the dye in the cloth, thus making a "fast 
color." The most common mordants are alum, salts 
of tin and of iron. In dyeing, the cloth is first 
dipped into a solution of the mordant, and then into 
one of the dye-stuff. The mordant, by means of a 
stamp, may be applied to the cloth in the form of a 
pattern, and, when it is afterward washed, the color 
will be removed, except where the mordant fixed it 
in the printed figure. The same dye will produce 
different colors by a change of mordants. — Example: 
Madder, with iron, gives a fine purple ; with alum, a 
pink ; and with iron and alum, a chocolate. This 
principle lies at the basis of dyeing "prints."* 

* A calico printing-machine is very complex. The cloth passes between 
a series of rollers, upon which the corresponding mordant is put, as ink is 
on type. A single machine sometimes prints from twenty sets of rollers ; 
yet each impression follows the other so accurately that, when the cloth 
has passed through, the entire pattern is printed upon it, with the different 
mordants, more perfectly than any painter could do it, and so rapidly that 



236 ORGANIC CHEMISTRY. 

Coloring Substances. — Madder is the root of a 
plant found in the East, and extensively cultivated 
elsewhere. When first dug, it is yellow, but by ex- 
posure it becomes red. It is used in dyeing the 
brilliant Turkey-red. The coloring principle, which 
is named alizarin, is identical with that derived 
from anthracene, a hydrocarbon found in coal-tar 
(see p. 224), and is now made in large quantities 
from that source. Cochineal is a dried insect that in 
life feeds upon a species of cactus in Central America. 
The coloring matter is called Carmine. It yields the 
brightest crimson and purple dyes.* Brazil-wood 
furnishes a red which is not very permanent. It is 
used for making red ink. The indigo of commerce 
is obtained from a bushy plant found in the East 
Indies. By fermenting for some days in vats of 
water, the coloring matter is developed. Reducing 
agents change indigo into a soluble and colorless 
substance by the absorption of H.f It is then called 
"white indigo." In this form it is extensively used 
in dyeing. The cloth becomes permanently colored on 

a mile of cloth, has been printed, with four mordants, in an hour. The 
cloth, when it leaves the printing-machine, though stamped with the mor- 
dants in the form of the figure, betrays nothing of the real design until 
after being dipped in the dye, which, acting on the different mordants, 
brings out the desired colors. The print is now washed, glazed, and fitted 
for the market. 

* The purple of which we read in ancient writings was a secret with the 
Tyrians. King Hiram, we learn, sent a workman to Solomon skilled in this 
art. The dye was obtained from a shell-fish that was found on the coast of 
Phoenicia. Each, animal yielded a tiny drop of the precious liquid. " A yard 
of cloth dipped twice in this costly dye was worth $150." 

t Place a little powdered indigo in a test-tube of H 2 0, and add zinc 
filings and caustic soda. On heating, the indigo becomes colorless. If it is 
now exposed to the air in a saucer, it will turn blue again. 



DYES AND DYEING. 237 

exposure to the air, when the insoluble blue indigo 
is formed in its fibers.* Logwood is so named be- 
cause imported in logs. It is the heart of a South 
and Central American tree. With a mordant of iron, 
it dyes black. Litmus is obtained from a variety of 
lichens common along the southern coast of Europe. 
Its juice is colorless, but by the action of water, air, 
and NH 3 , it assumes a rich purple blue. Leaf-green 
(chlorophyl), as found in plants, is a resinous sub- 
stance containing several coloring matters. It seems 
to be developed by the action of the sunbeam. Plants 
removed from a dark cellar to the sunlight, rapidly 
turn green. 

Tannic Acid, tannin (C, 4 H l0 9 ), is found in the 
leaf and bark of trees, f — Example : Oak, hemlock. 
Nut-galls are excrescences which are formed by the 
puncture of an insect on the leaves of a certain 
species of oak. Tannin has an astringent taste, is 
soluble in water, and hardens albuminous substances, 
as gelatin. 

Tanning. — After the hair has been removed from 
the skins by milk of lime, they are soaked for days, 
the best kinds for months, in vats full of water and 
ground oak or hemlock bark (tan-bark). The tannic 
actd of the bark is dissolved, and, entering the pores 
of the skin, unites with the gelatin, forming a hard, 

* One of the triumphs of synthetical chemistry has been the artificial 
preparation of indigo. 

t This astringent principle is widely diffused. There are several com- 
pounds which possess similar properties, yet differ in chemical composition. 
The tannin of the oak is called quercitannic acid ; that of nut-galls^ gallotannic 
acid ; that of tea, theitannic, and that of coffee, caffeotannic acid. 



238 ORGANIC CHEMISTRY. 

insoluble compound which is the basis of leather. 
Leather is blackened by washing the hide on one 
side with a solution of copperas. The tannic acid 
unites with the iron, forming a tannate of iron — an 
ink. In the same way, drops of tea on a knife-blade 
stain it black. 

Ink is made by adding a solution of nut-galls to 
one of copperas. The iron tannate thus formed has 
a pale blue-black color, as in the best writing-fluids ; 
by exposure to the air, the Fe absorbs more 0, the 
ink darkening in color until it is a deep black. Gum 
is added to thicken and regulate the flow of the fluid 
from the pen. Creosote, or corrosive sublimate, is 
used to prevent moldiness. Steel pens are corroded 
by the free H 2 S0 4 contained in the ink, but gold pens 
are not affected by it.* 

Gallic Acid (C 7 H 6 5 ) is best prepared from nut- 
galls, by fermentation of the tannic acid which they 
contain. Pyrogallic acid can be obtained by the 
sublimation of gallic or -gallotannic acid. It is exten- 
sively used in photography for the purpose of devel- 
oping the latent image in the collodion film after 
exposure to the action of the light. (See p. 172.) 

Linseed Oil is a drying oil, as it is termed — i. e., 
it absorbs from the air, and hardens by exposure. 

* The following is an instructive experiment, illustrating the manner of 
making ink, of removing stains with oxalic acid, and also the relative 
strength of the acids and alkalies : Take a large test-tube, and add the 
following re-agents in solution, cautiously, drop by drop, watching the result 
and explaining the reactions : 1, iron sulphate {copperas) ; 2, tannic acid 
(tannin) ; 3, oxalic acid ; 4, sodium carbonate (sal-soda) ; 5, hydrochloric acid 
(muriatic) ; 6, ammonia (hartshorn) ; 7, nitric acid (aquafortis) ; 8, caustic 
potash ; 9, sulphuric acid (oil of vitriol.) 



THE ALBUMINOUS BODIES. 239 

It is expressed from flaxseed, which furnishes about 
one fifth of its weight in oil. Boiled oil is made by 
heating the crude oil with litharge, which entirely 
dissolves and greatly increases the drying property of 
the oil. Linseed oil is used in mixing paints and 
varnishes. Putty consists of linseed oil and whiting, 
well mixed. The chief ingredients of printers' ink 
are linseed oil, heated until it becomes thick and 
viscid, and lamp-black. 



THE ALBUMINOUS BODIES. 

These are albumin, casein, and fibrin. Owing to 
the complexity of their composition, no satisfactory 
formula can be assigned to them. The molecule of 
albumin has been stated as C 72 H MO N l8 S0 22 , but it is 
very uncertain.* 

Albumin is found nearly pure in the whites of 
eggs,f hence the name {albus, white). It exists 
as a liquid in the sap of plants, the humors of 
the eye, serum of the blood, etc. ; and as a solid 
in the seeds of plants, and the nerves and brains 
of animals.! 



* Many chemists regard albumin, casein, fibrin, etc., as isomeric, and 
capable of being converted by the vital force one into the other. These 
bodies are sometimes called Protein (protos, first) on the supposition that 
they were derived from a single azotized principle named protein. 

t Strange to say, " the venom of the rattlesnake is isomeric with the 
'the whites of eggs.' " 

X This principle is of very great importance, as albumin may thus be 
carried by the blood through the system, but when once deposited it can 
not be dissolved and washed away again. 



240 ORGANIC CHEMISTRY. 

Properties. — It is soluble in cold, but insoluble in 
hot H 2 0. At a temperature of about 140° F., it 
coagulates. This change we always see in the cooking 
of eggs ; yet nothing is known of its cause. Alcohol, 
corrosive sublimate, acids, creosote, and solutions of 
copper, lead, silver, etc., have the power to coagulate 
albumin. In cases of poisoning by these substances, 
the white of eggs is therefore a valuable antidote, as 
it wraps them in an insoluble covering, and so pro- 
tects the stomach. 

Casein (caseus, cheese) is found in the curd of 
milk. In the presence of an acid it coagulates, and 
thus milk curdles after it sours. Rennet (the dried 
stomach of a calf) is used to coagulate milk in the 
process of cheese-making, but the cause of its action 
is not understood. 

Milk is a natural emulsion, composed of exceed- 
ingly minute globules diffused through a transparent 
liquid. The globules consist of a 
thin envelope of casein filled with 
butter. Being a trifle lighter than 
H 2 0, they rise to the surface as 
cream. Churning breaks these 
coverings, and gathers the butter 
into a mass. Milk contains some 
sugar, which, by a peculiar change mk und J th£ ^ZZpe. 
termed " lactic fermentation," is 
converted into lactic acid. The casein seems to act 
as a ferment in hastening this oxidation, and, by its 
decay, produces the offensive odor. In the " souring 
of milk, the milk-sugar (C, 2 H 24 0,,) disappears, and 




• 



THE ALBUMINOUS BODIES. 



241 



Eig. 74. 




Fibrin, or Muscle. 



lactic acid (C 3 H 6 3 ) gradually takes its place. It is 
an excellent illustration of a complex molecule break- 
ing up into simple ones. 

Fibrin constitutes chiefly the fibrous portion of 
the muscles. If a piece of lean beef be washed in 
clean H 2 until all the red color disappears, the 

mass of white tissue which 
will remain is called fibrin. 
Like albumin, it exists in 
two forms — as a liquid in the 
blood, and as a solid in the 
flesh. The clotting of blood 
is due to the coagulation of 
the fibrin. (See " Physiol- 
ogy," p. 108.) 
Vegetable Albuminoids. — Vegetables contain sub- 
stances which are scarcely to be distinguished from 
the albuminous bodies derived from animal sources. 
If wheat flour be made into a dough, and then 
kneaded in water until the soluble portion is washed 
away, the tough, sticky mass which will remain is 
called gluten. It is a nitrogenous substance, allied to 
albumin. It exists most abundantly in the bran of 
cereal grains. 

By treating peas as we do potatoes in forming 
starch, and then adding a little acid to the water 
which is left after the starch settles, an albuminous 
substance is deposited, which is thought to be iden- 
tical with casein. The Chinese use it largely for 
cheese. It is found abundantly in the seeds of peas, 
beans, etc., and is termed legumin. 



242 ORGANIC CHEMISTRY. 

Putrefaction. — Owing to the complex structure of 
albuminous substances, and the presence of N, they 
readily oxidize, and form new and simple compounds. 
This breaking up of the organic structure is called 
putrefaction, and is but a special kind of fermenta- 
tion. The activity of the ferment probably explains 
the danger physicians incur in dissecting dead 
bodies. The least portion of the decomposing mat- 
ter entering the flesh, through a scratch, is liable 
to be fatal. The absence of H 2 retards chemical 
change, and, therefore, meats, apples, etc., are pre- 
served by drying. * Salt acts by hardening the 
albumin, by absorbing the juice of the meat, and by 
covering as brine, and so warding off the attacking 
; but as it dissolves some of the salts and other 
valuable elements, it makes the meat less nutritious. 



Gelatin. — Hot water dissolves a substance from 
animal membranes, skin, tendons, and bones, f which, 

* The cold also protects from chemical change. The bodies of mam- 
moths have been found in the frozen soil of the Arctic regions so perfectly 
preserved that the dogs ate the flesh. How long the animals had been 
there we can not tell, but certainly for ages. In 1861 the mangled remains 
of three guides were found at the foot of the GKLaoier de Boisson, in Switzer- 
land. They had been lost in an avalanche on the plateau of Mont Blanc, 
forty-one years before. 

t Analysis. (Berzelius.) 

Gelatin 32.17 

Blood-vessels 1.13 

Phosphate of lime 51.04 

Carbonate of lime 11.30 

Pluoride of calcium 2.00 

Phosphate of magnesia 1.16 

Chloride of sodium 1.20 

100.00 

t Bones consist of organic and mineral matter combined. By soaking a 



DOMESTIC CHEMISTRY. 243 

on cooling, forms a yielding, tremulous mass called 
gelatin. In calves-foot jelly, soups, etc., it is well 
known.* Glue is a gelatin made from bones, hoofs, 
horns, etc., by boiling in H 2 0, and then evaporating 
the solution. Isinglass is a very pure gelatin, ob- 
tained from the air-bladders of the cod, sturgeon, 
and other fish. Size is a gelatin prepared from the 
parings of parchment. It is used for sizing paper 
in order to fill up the pores and prevent the ink 
from spreading, as it does on unsized or blotting- 
paper. 



DOMESTIC CHEMISTRY. 

In the chemistry of housekeeping there are some 
points not yet mentioned which may now be profit- 
ably discussed. 

Making Bread. — Flour consists of starch, gluten, 
and a little dextrin and sugar. 

The oily matter and the salts — of which there are 
from 1 to 2 per cent, in wheat — are contained 
mainly in the bran. The process of making the 
"sponge" is purely mechanical. When the sponge is 
set in a warm place to rise (as heat favors chemical 

bone in HC1 the mineral matter will all be dissolved, and the organic matter 
left in the original shape of the bone, but soft and pliable. If, instead, the 
bone be burned in the fire, the organic matter will be removed, and the 
mineral left white and porous. (See " Physiology," p. 20.) 

• * As an article of food it is of very little nutritive value. It may answer 
to dilute a stronger diet, but of itself does little to build up the body of an 
invalid. Beef -tea, even, is now thought to have little nourishing property, 
its principal office being to act as a stimulant. 



244 ORGANIC CHEMISTRY. 

change), the yeast, yeast-cake, or emptyings,* as the 
case may be, induce a rapid fermentation, converting 
the sugar into alcohol and C0 2 . This gas is diffused 
through the mass, and, being retained by the 
tenacious dough, causes it to " rise " — i. e., to swell 
and become porous. The next step includes the 
addition of flour, and a laborious process of " knead- 
ing." The latter diffuses the half -fermented sponge 
through the dough ; it also breaks up into smaller 
ones the bubbles of gas entangled in the gluten, and 
makes the bread fine-grained. After a second rising, 
the dough is molded into loaves, which are set aside 
to perfect the fermentation. AVhen they are finally 
placed in the oven, the heat expands the C0 2 , and 
increases the porosity of the bread ; the starch 
granules are broken up ; and the alcohol is vapor- 
ized, and it and the H 2 partly driven off. The 
surface becomes dry and hard, and, losing a part of 
its chemically combined water, is partially converted 
into a substance allied to caramel, thus forming the 
crust.* If the temperature of the oven is right, 
the cells of the bread will have sufficient strength to 



* Milk-emptyings are sometimes used in making bread. In this case the 
mixture of flour and milk, kept at a temperature of about "blood heat," 
rapidly develops yeast, which produces fermentation. If the heat is much 
above this, the plant will be killed, and the milk be merely turned to lactic 
acid. Oftentimes, too, the side of the dish, near the fire, may be warm enough 
to produce yeast, and to generate C0 2 and alcohol, while on the opposite side 
lactic acid is being formed. A uniform temperature is necessary, and this 
can best be obtained by placing the dish of emptyings in a kettle of warm 
water on the stove hearth. 

t A shiny coat is given to the loaf ("rusk") by moistening the crust 
after the bread is baked, thus dissolving some of the dextrin, which is 
also contained in the crust. This quickly dries on returning it to the oven. 



DOMESTIC CHEMISTRY. 245 

retain their form after the gas and vapors have 
escaped. If the heat is not sufficient, or if there 
is too much water in the dough, the C0 2 escapes, 
the cells, not being sufficiently hardened, collapse, 
and the bread is " slack-baked." If the oven is 
too hot, the crust forms too quickly over the sur- 
face of the loaf, preventing the escape of the C0 2 , 
which accumulates at the center, making the loaf 
hollow. 

Stale Bread. — New bread consists of about 45 per 
cent, water. In stale bread this disappears, but may 
be brought to view again by heating the loaf in a 
close tin vessel. 

Aerated Bread is made in the following manner : 
Flour and salt are put in a revolving copper globe, 
into which H 2 0, charged with C0 2 , is admitted. 
When well mixed, a stop-cock is turned, and the 
dough is driven out by the elastic force of the gas, 
into pans ready for baking. 

Sour Bread results from a neglect to arrest the 
first stage of the fermentation, thus allowing the 
second stage to commence, and acetic acid to be 
formed. The acid is neutralized by an alkali, as sale- 
ratus, or soda. 

Griddle-cakes are raised by the addition of some 
ferment, as yeast ; but the second, or acetic stage, is 
always reached. The "batter" then tastes sour, and 
is sweetened by saleratus or soda. The acetic acid 
combines with the metallic- base, forming a harmless 
salt, which remains, while the C0 2 bubbles up through 
the batter, making it " light." 



246 ORGANIC CHEMISTRY. 

Raising Biscuit. — In raising biscuit or cake, soda 
and cream of tartar* are most commonly used. The 
C0 2 is set free, and, escaping as a gas, makes the 
dough porous, while the sodium and potassium 
tartrate (Rochelle salt) which is formed, remains. 
Ordinary " baking-powders " are merely cream of tar- 
tar and soda. A variety invented by Professor 
Horsford contains acid calcium phosphate (see note, 
p. 142); this, reacting upon the "soda," forms cal- 
cium and sodium phosphates, both of which are 
materials for bone-making, f Soda and HC1 are also 
used in baking. By heat, these ingredients are re- 
solved into H 2 0, C0 2 , and NaCl. The H 2 and C0 2 
raise the bread, while the common salt seasons it. 
There is a difficulty in procuring pure acid, and in 
mixing the ingredients in their combining propor- 
tions. Sal-volatile (ammonium sesquicarbonate, p. 
13 7) is often used by bakers for raising cake. This 
should volatilize into two gases, NH 3 and C0 2 , on the 
application of heat, but in practice a portion is com- 
monly left hidden in the cake, and may be detected 
by the odor. Alum is often employed by bakers to 
whiten bread, and to improve the appearance of 
bread made from inferior flour. 

* Cream of tartar is often adulterated with, plaster, lime, chalk, or flour. By 
dissolving in water, these impurities can be detected, as they form an insoluble 
precipitate ; but in milk, as commonly used in cooking, they are not noticed. 

t It is doubtful whether ordinary yeast-powders, or cream of tartar and 
soda, make as healthful food as the regular process of fermentation. There 
is frequently a portion of the powders left uncombined, and always a salt 
formed which may perhaps interfere with the action of the gastric juice. 
Sometimes, indeed, we find biscuit and cake yellow, and even spotted with 
bits of saleratus; yet, through a false economy, such food is too often 
" eaten to save it." 



PRACTICAL QUESTIONS. 247 

Toasting Bread. — By toasting, bread becomes 
much more digestible, as the starch is converted 
largely into dextrin, which is soluble. The charcoal 
which may be formed when the heat has disorgan- 
ized the bread and driven off the water, also acts 
favorably on the stomach by absorbing in its pores 
noxious gases, as in " crust-coffee." 

Cooking Potatoes. — A raw potato is indigestible, 
but by cooking the starch granules absorb the water 
of the potato, burst, and make it " mealy." If the 
potato contains more H 2 than the starch can imbibe, 
it is called " watery." 



PRACTICAL QUESTIONS. 

1. How would yon prove the presence of tannin in tea? 

2. How wonld yon test for Pe in a solution? 

3. Why can we settle coffee with an egg? 

4. How wonld yon show the presence of starch in a potato? 

5. Why is starch stored in the seed of a plant? 

6. Why are nnbleached cotton goods dark colored? 

7. Why do beans, rice, etc., swell when cooked? 

8. Why does decaying wood darken? 

9. How wonld yon show that C exists in sngar? 

10. Why do fruits lose their sweetness when over-ripe? 

11. Why does maple-sap lose its sweetness when the leaf starts? 

12. Shonld yeast cakes be allowed to freeze? 

13. Why will wine sonr if the bottle be not well corked ? 

14. Why can vinegar be made from sweetened water and brown paper? 

15. Why shonld the vinegar-barrel be kept in a warm place? 

16. Why does "scalding 1 ' check the "working" of preserves? 

17. Is the oxalic acid in the pie-plant poisonons? 

18. How may ink-stains be removed? 

19. Why is leather black on only one side? 

20. Why do drops of tea stain a knife-blade ? 

21. Why will not coffee stain it in the same way? 

22. Why does writing-fluid darken on exposure to the air? 



248 ORGANIC CHEMISTRY. 

23. Why does ink corrode steel pens? 

24. How does a bird obtain the CaC0 3 for its egg-shells? 

25. Why will tallow make a harder soap than lard? 

26. Why does new soap act on the hands more than old? 

27. What is the shiny coat on certain leaves and fruits? 

28. Why does turpentine burn with so much smoke? 

29. Why is the nozzle of a turpentine bottle so sticky? 

30. Why does kerosene give more light than alcohol? 

31. What is the antidote to oxalic acid? Why? 

32. Would you weaken camphor spirits with water? 

33. What is the difference between rosin and resin? 

34. Why does skim-milk look blue and new milk white? 

35. Why does an ink-spot turn yellow after washing with soap? 



CONCLUSION. 

Chemistry of the Sunbeam. — The various plant- 
products of which we have spoken in Organic 
Chemistry, when burned, either in the body as food 
or in the air as fuel, give off heat. This was 
garnered in the plant while growing, and came from 
that great source of heat — the sun. Thus all vegeta- 
tion contains the latent heat of the sunbeam, ready 
to be set free upon its own oxidation. The coal, 
even, derived as it is from ancient vegetation, hidden 
away in the earth, is thus a mine of reserved energy. 
Those black diamonds we use as fuel become, in the 
eye of science, crystallized sunbeams, fagots of energy, 
ready to impart to us at any moment the heat of 
some old Carboniferous day. A field of growing 
wheat reaches out its tiny arms, and, tangling in 
stalk and grain the heat of sultry mid-summer, re- 
tains it against the bleak December. The oil-well 
spouts not alone unsavory kerosene, but liquid sun- 
beams, the gathered store of a geologic age. As we 
warm ourselves by our fires, or sit and read by our 
oil and gas lights, how strange the thought that 
their light and heat streamed down upon the earth 
ages ago, were absorbed by the grotesque leaves of 
the old coal forests, and kept safely stored away by 



250 ORGANIC CHEMISTRY. 

a Divine care in order to provide for our comfort ! The 
present warmth of our bodies all came from the same 
source — the sun. It mostly fell in the sunbeams of 
last summer upon our gardens and fields, was pre- 
served in the potatoes, cabbage, corn, etc., we have 
eaten as food, and to-day reappears as heat and 
motion. Every blow, every breath, and every step, 
are but transformations of solar rays, and can be 
estimated in sunshine. 

The Sun the Source of Power. — The sun warms, 
enlivens, and animates the earth. * In the laboratory 
of the leaf, he produces the most wonderful chemical 
changes. We see his handiwork in the building of 
the forest, the carpeting of the meadow, and the 
tinting of the rose. On the ladder of the sunbeam, 
water climbs to the sky, and falls again as rain. 
The very thunder of Niagara is but the sudden un- 
bending of the spring that was first coiled by the 
sun in the evaporation from the ocean. Up to the 
sun, then, we trace all the hidden manifestations of 
power. Yet the energy that produces such intricate 
and wide-extended changes is only one twenty-three 
hundred millionth part of the tide that flows in 
every direction from this great central orb. But 
what is our sun itself save a twinkling star beside 
great suns like Sirius, Regulus, and Procyon, whose 
brilliancy in the far-off regions of space drowns our 
little sun as the dazzling light of day does the 
smoldering blaze of some wandering hunter? 

Changes of Matter. — Chemical changes are taking 
place wherever we look — on land or sea. The hard 



CONCLUSION. 251 

granite crumbles and molders into dust. The stout 
oak draws in the air, and solidifies it ; takes up the 
earth, and vitalizes it ; changes all into its own 
structure, and proudly stands monarch of the forest. 
But in time its leaves turn yellow and sere ; its 
branches crumble ; itself totters, falls, and dis- 
appears. Our bodies seem to us comparatively 
stable, but, with the rock and the oak, they too 
pass away. All Nature is a torrent of ceaseless 
change. We are but parts of a grand system, and 
the elements we use are not our own. The water 
we drink and the food we eat to-day may have been 
used a thousand times before, and that by the vilest 
beggar or the lowest earth-worm. In Nature all is 
common, and no use is base. Those particles of 
matter we so fondly call our own, and decorate so 
carefully, a few months since may have dragged 
boats on the canal, or waved in the meadow as grass 
or corn.* From us they will pass on their ceaseless 

* The truth, that matter passes from the animal back to the vegetable, 
and from the vegetable to the animal kingdom again, received, not long 
since, a curious illustration. For the purpose of erecting a suitable monu- 
ment in memory of Roger Williams, the founder of Rhode Island, his 
private burying-ground was searched for the graves of himself and wife. 
It was found that every thing had passed into oblivion. The shape of the 
coffins could only be traced by a black line of carbonaceous matter. The 
rusted hinges and nails, and a round wooden knot, alone remained in one 
grave ; while a single lock of braided hair was found in the other. Near 
the graves stood an apple-tree. This had sent down two main roots into 
the very presence of the coffined dead. The larger root, pushing its way to 
the precise spot occupied by the skull of Roger Williams, had made a turn 
as if passing around it, and followed the direction of the backbone to the 
hips. Here it divided into two branches, sending one along each leg to 
the heel, when both turned upward to the toes. One of these roots formed 
a slight crook at the knee, which made the whole bear a striking resem- 
blance to the human form. (These roots are now deposited in the museum 



252 ORGANIC CHEMISTRY. 

round to develop other forms of vegetation and life, 
whereby the same atom may freeze on arctic snows, 
bleach on torrid plains, be beauty in the poet's 
brain, strength in the blacksmith's arm, or beef on 
the butcher's block. Hamlet must have been some- 
what more of a chemist than a madman when he 
gravely assured the king that "man may fish with 
the worm that hath eat of a king, and eat of the 
fish that hath fed of the worm." 

Shakespeare expresses the same chemical thought 
when he again makes Hamlet say: 

" Imperious Csesar, dead and turned to clay, 
Might stop a hole to keep the wind away. 
Oh ! that the earth which kept the world in awe 
Should patch a wall to expel the winter's flaw 1 " 

Or when he makes Ariel sing: 

" Full fathom five thy father lies : 
Of his bones are coral made ; 
Those are pearls that were his eyes; 
Nothing of him that doth fade 
But doth suffer a sea change 
Into some thing rich and strange." 

Life and Death are thus throughout nature com- 
mensurate with and companions of each other. Oxy- 

of Brown University.) There were the graves, but their occupants had dis- 
appeared ; the bones even had vanished. There stood the thief— the guilty 
apple-tree— caught in the very act of robbery. The spoliation was complete. 
The organic matter— the flesh, the bones, of Roger Williams— had passed 
into an apple-tree. The elements had been absorbed by the roots, trans- 
muted into woody fiber, which could now be burned as fuel, or carved into 
ornaments ; had bloomed into fragrant blossoms, which had delighted the 
eye of passers-by, and scattered the sweetest perfume of spring ; more than 
£hat— had been converted into luscious fruit, which, from year to year, had 
been gathered and eaten. How pertinent, then, is the question, "Who ate 
Roger Williams ? " 



CONCLUSION. 253 

gen is the destroyer, and the sunbeam the builder. 
Oxygen tears down every living structure, and would 
bring all things to rest in ashes. The sunbeam re- 
invigorates, rebuilds, and rescues from the grasp of 
decay. Though they seem to be antagonists, oxygen 
and the sunbeam really work in harmony, and each 
supplements the labor of the other. Death alone 
makes life possible. 

Thus we have traced some of the wonderful proc- 
esses by which this world has been arranged to 
supply the varied wants of man. Wherever we have 
turned, we have found proofs of a Divine care plan- 
ning, conforming, and directing to one universal end, 
while from the commonest things, and by the sim- 
plest means, the grandest results have been attained. 
Thus does Nature attest the sublime truth of Revela- 
tion, that in all, and through all, and over all, the 
Lord God omnipotent reigneth. 



IV. 

Appendix 



TABLE OF THE ELEMENTS. 



Aluminium 

Antimony (Stibium).. 

Argon 

Arsenic 

Barium 

Bismuth 

Boron 

Bromine 

Cadmium 

Caesium 

Calcium 

Carbon 

Cerium 

Chlorine 

Chromium 

Cobalt 

Columbium 

Copper (Cuprum) 

Erbium 

Fluorine 

G-adolinium 

Q-allium 

Germanium 

Glucinum 

Gold ( Aurum) 

Helium 

Hydrogen 

Indium 

Iodine 

Iridium 

Iron (Eerrum) 

Lanthanum 

Lead (Plumbum) 

Lithium 

Magnesium 

Manganese 

Mercury (Hydrar- i 
gyrum) 1 



Symbol. 


Atomic 
Weight. 


Al 


27 


Sb 


120 


A 


20 


As 


75 


Ba 


137.4 


Bi 


208 


B 


11 


Br 


80 


Cd 


112 


Cs 


133 


Ca 


40 


C 


12 


Ce 


141 


CI 


35.5 


Cr 


52 


Co 


59 


Cb 


94 


Cu 


63.6 


E 


166 


E 


19 


ad 


156 


G-a 


69 


Ge 


72.3 


Gl 


9 


Au 


197 


He 


2 


H 


1 


In 


113.6 


I 


127 


Ir 


193 


Ee 


56 


La 


138.2 


Pb 


207 


Li 


7 


Mg 


24.3 


Mn 


55 


Hg 


200 



Molybdenum 

Neodymium 

Nickel 

Nitrogen 

Osmium 

Oxygen 

Palladium 

Phosphorus 

Platinum 

Potassium (Kalium). 

Praseodymium 

Ehodium 

Rubidium 

Ruthenium 

Samarium 

Scandium 

Selenium 

Silicon 

Silver ( Argentum) . . . 
Sodium (Natrium) . . . 

Strontium 

Sulphur 

Tantalum 

Tellurium 

Terbium 

Thallium 

Thorium 

Tin (Stannum) 

Titanium 

Tungsten (Wolfram) 

Uranium 

Vanadium 

Ytterbium 

Yttrium 

Zinc 

Zirconium 



Symbol. 



Mo 
Nd 
Ni 
N 

Os 
O 
Pd 
P 

Pt 

K 

Pr 

Rh 

Rb 

En 

Sm 

Sc 

Se 

Si 

Ag 

Xa 

Sr 

S 

Ta 

Te 

Tb 

Tl 

Th 

Sn 

Ti 

U 
V 
Yb 
Y 

Zn 
Zr 



Note. 
italics. 



-The names of metals are printed in Roman, non-metals in 



NAMES AND FORMULAS 



OF SOME OF THE 



MORE IMPORTANT CHEMICAL COMPOUNDS. 



Acid, acetic CH 3 CO.OH. 

" boric B(OH) 3 . 

" hydrochloric (muriatic) HC1. 

44 hydrocyanic (prussic) HON. 

" nitric HNO 3 . 

" oxalic (CO.OH) 3 . 

" salicylic C 6 H 4 (OH)CO.OH. 

" sulphuric H 2 S0 4 . 

" tartaric C 2 H 4 2 (CO.OH) 2 . 

Alcohol, amyl (fusel oil) C 5 H n OH. 

" ethyl (common alcohol) C 2 H 5 OH. 

" methyl (wood alcohol) CH 3 OH. 

Alum A1 2 3S0 4 ,K 2 S0 4 + 24H 2 0. 

Ammonium hydroxide (ammonia) NH 4 OH. 

" carbonate (NHJ 2 C0 3 . 

chloride NH 4 C1. 

" nitrate ]STH 4 K0 3 . 

Aniline C 6 H 5 NH 2 . 

Arsenic trisulphide (orpiment) As 2 S 3 . 

Arsenious oxide (arsenic) As 2 3 . 

Barium chloride BaCl 2 . 

" sulphate .BaSO*. 

Benzene (benzol) ... . '. C 6 H 6 . 

Cadmium iodide Cdl 2 . 

44 sulphide (cadmium yellow) CdS. 

Calcium carbonate CaC0 3 . 

44 chloride CaCl 2 . 

44 oxide (lime) CaO. 

" sulphate (gypsum) CaS0 4 ,2H 2 0, 



NAMES AND FORMULAS. 259 

Camphor C 10 H 16 0. 

Carbon dioxide (carbonic acid) C0 2 . 

" disulphide CS 2 . 

" monoxide CO. 

Chloral hydrate CCl 3 COH,H 2 0. 

Chloroform CHC1 3 . 

Cobalt nitrate Co2N0 3 . 

Copper sulphate (bine vitriol) CuS0 4 ,5H 2 0. 

Ether (snlphuric ether) (C 2 H 5 ) 2 0. 

Ferric chloride Fe 2 Cl 6 . 

Ferrons sulphate (green vitriol) FeS0 4 ,7H 2 0. 

41 sulphide FeS. 

1 Glycerin C 3 H 5 (OH) 3 . 

Hydrogen sulphide (sulphuretted hydrogen) H 2 S. 

Lead acetate (sugar of lead) Pb(CH 3 CO.O) 2 . 

" chloride PbCl 2 . 

M chromate (chrome-yellow) PbCr0 4 . 

" oxide (litharge) s PbO. 

(red lead) Pb 3 4 . 

Magnesium chloride MgCl 2 . 

" oxide (calcined magnesia) MgO. 

" sulphate (Epsom salts) MgS0 4 ,7H 2 0. 

Manganese dioxide (black oxide of Mn) „ Mn0 2 . 

" sulphate MnSO*. 

Mercuric chloride (corrosive sublimate) HgCl 2 . 

M oxide (red oxide of Hg) HgO. 

" sulphide (vermilion). HgS. 

Mercurous chloride (calomel) HgCl. . 

Nitro-benzene C 6 H 5 N0 2 . 

Potassium antimonyl tartrate (tartar emetic) K(SbO)C 4 H 4 O a ,^H 2 0. 

M carbonate (pearlash) K 2 CO s . 

" bicarbonate (saleratus) KHC0 3 . 

chlorate KC10 3 . 

" chromate K 2 Cr0 4 . 

*' bichromate K 2 Cr 2 7 . 

" ferricyanide K 3 FeCy 8 . 

*' ferrocyanide (prussiate of potash) K 4 FeCy 8 . 

" hydroxide (caustic potash) KOH. 

44 iodide KI. 



260 NAMES AND FORMULAS. 

Potassium nitrate (niter, saltpeter) KNO s . 

" permanganate KMn0 4 . 

" bitartrate (cream of tartar) KHC 4 H 4 O e . 

Silver nitrate (lunar caustic) A.gNO s . 

Sodium pyroborate (borax) Na 2 B 4 O 7 ,10H 2 O. 

" carbonate (soda) Na 2 C0 3 . 

" chloride (common salt) NaCl. 

" hydroxide (caustic soda) NaOH. 

" sulphate (Glauber's salt) ]STa 2 SO 4 ,10H 2 O. 

" potassium tartrate (Rochelle salt) NaKC 4 H 4 6 ,4H 2 0. 

Stannic sulphide (mosaic gold) SnS 2 . 

Strontium nitrate Sr2N0 3 

Sugar, cane Ci 2 H 22 On. 

" grape (glucose) C 6 H 12 6 . 

Turpentine.,. C 10 H 18 . 

Zinc sulphate ZnSO*. 



Directions for Experiments. 

The following simple suggestions will enable any student to perform all 
the experiments mentioned in this work. Many easy illustrations are also 
given in addition to those named in the text. Carefully compare them 
with those contained in the body of the book. The full-faced figures 
refer to the pages of the book, and the light-faced figures to the number 
of the experiment. 

INORGANIC CHEMISTRY. 

| . Indestructibility of Matter.— Two invisible substances are formed 
by the burning candle, as may be proved by the following experiments : 

1. Hold a cool, dry tumbler, or glass flask, over a candle-flame. The crlass 
will be immediately covered with a fine dew from the steam produced by 
the burning candle. 

2. Lower a lighted candle-end, fixed on a handle of wire, into a clean 
glass bottle, and loosely cover the mouth of the bottle with a piece of 
paper. After the flame has gone out, remove the candle ; pour a little clear 
lime-water (see p. 139) into the bottle, and shake. The lime-water becomes 
milky, while in another bottle in which no candle has been burned it will 
remain clear (prove this). This shows that the burning candle has formed 
an invisible substance, which, unlike air, can render lime-water turbid. 

Weight and Impenetrability of Gases. — 3. "Weigh a flask or bottle full 
of air, and again after the air has been exhausted by means of an air- 
pump. While on the balance, allow the air to enter again. 

4. Balance a bottle full of air, and then fill it with carbon dioxide (see 
p. 66). 

5. The impenetrability of air may be shown by plunging a tumbler, 
mouth downward, into water. The water rises but a short distance into the 
tumbler. 

3. Chemical JLction of light. — 6. Dissolve a little salt and a little 
silver nitrate in separate portions of water. On mixing the solutions, a 
white precipitate is formed, which, on exposure to sunlight, turns dark. 

Effect of Solution in Promoting Chemical Action. — 7. The sodium 
carbonate and tartaric acid may be intimately m ix ed by grinding them 
together in a mortar. No chemical action will take place till water is 
added. 

I I . Oxygen.— 8. Heat 4-5 grams of red oxide of mercury in a hard 
glass tube, sealed at one end. Mercury is deposited on the sides of the tube 
beyond the flame, and a gas is given off which may be proved to be O by 
its kindling a match on which a spark has been left. By continuing the 
experiment, all of the HgO can be converted into Hg and O. 



262 DIRECTIONS FOR EXPERIMENTS. 

9. Put into a dry test-tube a few grams of pure potassium chlorate, and 
heat cautiously. The test-tube may be supported by a strip of thick paper 
twisted around it at the top. Move the tube to and fro through the flame at 
first, until it becomes fully heated ; keep the tube inclined, and not perpen- 
dicular, letting the flame strike the side rather than the bottom. Hold the 
thumb lightly over the mouth of the tube. The salt melts quietly, and then 
begins to decompose, with the appearance of boiling. That O is given off is 
proved as in Ex. 8. "When no more gas is evolved, allow the salt to cool, 
shaking it gently to prevent its attaching itself to the tube. The residue is 
no longer a chlorate, and gives out no yellow gas if moistened with H 2 S0 4 , 
but will yield a white precipitate with AgNO a , which shows it to be a chloride. 

10. Most of the following experiments may be performed in test-tubes as 
above, but, when it is desirable to make a larger quantity of O, one ounce 
of potassium chlorate is very carefully pulverized, and mixed with half that 
quantity of black oxide of manganese.* Be careful not to grind them to- 
gether. The mixing is effected by placing them both on sheets of clean 
paper, and pouring them back and forth from one sheet to the other until 
the mixture has a uniform gray color. Place the mixture in a flask; fit a 
cork to the nozzle ; then withdraw the cork, and with a round file bore a 
hole through it just large enough to admit a glass tube bentt as shown in 
Pig. 1. Return the cork and tube, arrange the apparatus as shown in the 
figure, and apply the heat. This must be done very cautiously at first, hold- 
ing the lamp in the hand, and moving it around so that the flame may 
strike all the lower part of the flask, and thus expand it uniformly. Be 
careful, also, that no draft of cold air strikes against the heated glass. The 
first few bubbles of gas will consist mainly of the air contained in the flask, 
and should not be caught. When the gas begins to pass over freely, 
diminish the heat. When the gas ceases, remove the stopper from the flask, or lift 
the end of the tube out of the water ; otherwise, as the flask cools, the water in 
the tube will rush back into the flask, and break it. "When the retort is nearly 
cool, pour in some warm water to dissolve the residuum, which may then 
be poured out, and the flask dried for future use. 

Instead of bending the glass tubing, it may be cut into short lengths, 
and the pieces joined by bits of rubber tubing. The advantage of this is 
that the flexible joints are not liable to break, and the apparatus may be 
more easily moved. "Where a large quantity of O is to be made, a copper 



* In order to test the purity of the materials, and thus avoid any danger of an ex- 
plosion, it is well, previous to putting the mixture in the flask, to place a little in an 
iron spoon, and heat it over the lamp. If the gas pass off quietly, no danger need be 
apprehended. 

t A glass tube may be bent at any point by softening that part in the flame of 
an ordinary gas-burner. Practice alone will give the required expertness. The fol- 
lowing points should be observed : 1. Keep the tube slowly turning between the 
fingers, so that it may be equally heated on all sides ; 2. Do not twist or pull the tube 
while heating ; 3. Do not bend it until very soft ; if not hot enough, the elbow will 
be flattened. Blowing gently into the tube at the moment of bending also prevents 
flattening. 



DIRECTIONS FOR EXPERIMENTS. 263 

retort and rubber tubing will be found cheap and convenient. Xo especial 
care is then needed in managing the heat.*— In place of the pneumatic 
tub, a pail or a tin pan may be used, letting the bottle rest on a shelf, as 
in Fig. 8, or on a couple of bricks.— The bottles for collecting the gas may- 
be the regular "deflagrating jar" of the chemist, or the common "packing 
bottle " of the druggist. They are to be sunk in the water of the pneumatic 
tub, and filled ; then inverted, and lifted upon the shelf, carefully keeping 
the lower edge of the bottle under the water. The bottles may also be filled 
from a pitcher, then closed with the hand or a plate, and quickly inverted 
and placed on the shelf in the tub or pan ready for use. As soon as a 
bottle is filled with gas, a plate may be slipped under the mouth, and thus, 
leaving enough water in the plate to cover the lower edge, be set aside, as 
in Pig. 1. Gras may be passed from one jar to another in the manner 
shown in Fig. 18.— While the gas is being collected, the water from the 
bottles which are filling may cause the tub to overrun ; to prevent this, 
arrange a siphon to carry off the water into a pail below the table.— When 
a jar of gas is wanted for use, slip a plate under the mouth, or simply close 
it with the hand, and, lifting the jar out, carry it to the table, and place it 
mouth upward. Uncover only when the experiment is ready to be per- 
formed, as the gas will slowly diffuse. 

I 3.— 11. The experiment with the candle may be very strikingly per- 
formed by filling a common fruit- jar with O, and another with N. The 
covers may be loosely laid on top, and the lighted candle passed quickly 
from one to the other, as mentioned in note on page 30. The candle 
may be simply stuck on the end of a bent wire, as in Pig. 15, but it is much 
neater to have the tinsmith fit a little cup for its reception. 

I 4.— 12. If brimstone be used in the experiment with S, and it fails to 
light readily, pour upon it a few drops of alcohol, and then ignite. 

13. Worn-out watch-springs can be obtained gratis of any jeweler, and 
may be easily straightened by slightly heating, and then drawing them be- 
tween the fingers. If the end of each spring be strongly heated, and then 
pounded with a hammer on any smooth, hard surface, the temper may be 
drawn, and the edge sharpened. Make a slit with a knife in the side of a 
match, into which insert the edge of the spring. Take a piece of zinc or tin 
large enough to cover the mouth of the jar containing the O, and make a 
hole through it with a nail. Pass the other end of the spring through this 
hole, and then through a thin cork. The spring is now ready for burning. 
The metal cover will prevent the flame from coming out of the jar and 
burning one's hand, and the cork will hold the spring in its place.t When 



* If, during the operation, the gas suddenly ceases to come off, remove the flame, and 
ascertain whether the delivery-tube is not choked up, which would result in a very violent 
explosion of the retort. 

t It is well to obtain several pieces of thin board or shingles, about six inches square, 
bore a small hole in the center, and insert a match end or small ping. These may be 
used as covers in most experiments where a deflagrating spoon is to be employed. The 
handle of the spoon is passed through this hole, and held in place by the small plug. 



264 DIRECTIONS FOR EXPERIMENTS. 

the match is ignited, and then lowered into the jar of O, the spring should 
not reach more than half-way to the bottom, and should be pushed down 
as it burns. A cheap packing bottle should be used, as the glass is 
frequently broken by the melted globules of iron. Do not fill it quite full of 
gas, as then, on inverting, a little water will be left at the bottom, or some 
fine sand may be thrown into the jar before the experiment. The illustra- 
tion may be repeated with a coil of fine iron wire. The springs from an 
old hoop-skirt burn nicely in O. 

14. When S, P, charcoal, a wax candle, Na, and other substances are 
to be burned in O, they may be supported on the end of pieces of glass 
tube bent like the letter J, and left open at the shorter end only. Por this 
purpose, covers must be provided with holes large enough for the glass 
tube to pass through. Or a "deflagrating spoon" may be readily extem- 
porized to contain the phosphorus. Hollow a small piece of chalk, and at- 
tach a wire to it, which may then be secured to a metal top, as in the case 
of the watch-spring. This need not be pushed down into the jar as the 
burning progresses. Be careful to cut the phosphorus under water, to dry 
it carefully with blotting-paper, and not to handle it. The fumes are very 
disagreeable, and should not be inhaled or allowed to escape into the room. 
They soon dissolve when shaken with a little water. 

I 5-— 15. In burning bark charcoal in O, force the gas into the bottle 
through a bit of rubber tubing at the mouth. By placing this at one side, 
the gas is given a rotary motion, and the sparks of ignited charcoal will 
drive around the bottle in a beautiful maelstrom of fire. The gas may be 
forced in from a rubber bag, and this striking effect easily produced. 

16. Arrange a receiver upon the bed-plate of the air-pump so that O 
may be admitted from a gas-bag by turning a stop-cock. Put under the re- 
ceiver an ignited tallow candle, with a big wick. Exhaust the air until the 
flame goes out, and there is left only a coal of fire. Admit the air, and it 
will have no effect to restore the blaze. Porce in some O quickly, and the 
coal will burst instantly into a brilliant white light, brighter than at the 
first. 

17. The oxidation of one solid by means of nascent O, liberated from 
another solid, can be shown as follows : Heat about five grams of potassium 
nitrate (saltpeter) in a test-tube until it melts quietly. Remove the lamp, 
and throw in pieces of S as large as peas, when they burn with an intensely 
bright flame. The heat is often sufficient to melt the glass, and the pre- 
caution should be taken to hold it over an iron plate or sand-bath. Or melt 
a quarter of a pound of saltpeter in an evaporating dish ; an ordinary tin 
cup will answer. Put it on some burning coals in a draught to carry off 
the fumes. Plunge into the liquid a piece of bark-charcoal, strongly ignited. 
The oxygen of the saltpeter will support the combustion, and the charcoal 
will deflagrate in a rushing volcano of scintillations. 

23. Ozone.— 18. Scrape off the white coating of a stick of phosphorus 
under water. Place it in a wide-mouth liter-bottle full of air, with about a 
teaspoonful of water at the bottom. Close the mouth of the bottle with 
a glass plate, and expose the whole for an hour or two to a temperature of 



DIRECTIONS FOR EXPERIMENTS. 265 

15° or 20° C. Then invert the neck of the bottle in crater, and allow the phos- 
phorus to fall out. Replace the glass plate, and withdraw the bottle and its con- 
tents froni the water. The phosphorus in this experiment undergoes a slow ox- 
idation, during which a little ozone is formed, and is left mixed with the air ; 
but the ozone will be again destroyed if it is left too long with the phosphorus. 

19. Put in an evaporating dish a little starch ; cover it with water in 
which a few crystals of potassium iodide have been dissolved, and heat. 
Stir the liquid, to prevent lumps. "When cooked, immerse in the paste slips 
of white blotting or clean writing-paper, and hang them up to dry. They 
must be moistened when used. 

20. Let some ozone pass into a clean bottle containing a little pure 
mercury. Shake the whole very carefully. The metal will change so as to 
act like an amalgam of tin and mercury, and will form a mirror on the 
sides of the bottle. 

28. Nitrogen.— 21. The phosphorus will, without the aid of heat, 
gradually remove the O from the air, forming phosphorus trioxide 
(P 2 O s \ which will be dissolved by the water, and in a day or two the 
gas which is left will be nearly pure X. To show the proportion of O and 
of X in common air : Take a long glass tube ; seal one end air-tight ; with 
a camers-hair brush and black paint mark upon the outside the division 
into fifths, and introduce a bit of phosphorus on the end of a long wire. 
Place the tube upright, with its open end under water. The water will 
gradually rise in the tube until it fills one fifth of the tube. 

3 | .—22. For making HX0 3 , take equal weights of sodium or potassium 
nitrate and strong sulphuric acid. The fumes may be caught in an 
evolution-flask, which is kept cool by water. "When the retort is partially 
cooled, at the conclusion of the process, pour in a little warm water, to dis- 
solve the potassium sulphate, otherwise the retort may break by the crystal- 
lization of the salt. 

23. To show the effect of HX0 3 upon the metals, procure bits of tin 
and copper from the tinsmith. Take six wine-glasses, and place them in a 
row upon ordinary soup-plates containing a little water. Cover each with 
a beaker-glass or bell- jar. In one put a strip of copper, in another a little 
mercury, in another a piece of pure tin (not tinned iron), in another a snip 
of zinc, in another a new iron nail, in the last a bit of platinum wire or 
foil. Pout strong nitric acid upon each, and cover immediately. The copper, 
mercury, and zinc dissolve with a violent evolution of gas. The tin is oxid- 
ized to a white powder, while the iron and platinum are unaffected. Touch 
the iron with a piece of zinc, and it begins to dissolve. Put another new 
nail in dilute nitric acid, and it is rapidly dissolved. 

24. Mix slowly together one ounce oil of vitriol and two ounces of the 
strongest nitric acid. When cold, dip paper into the mixture, and quickly 
wash with cold water and dry. The paper will burn with a flash like gun- 
powder. To avoid getting the acid on the hands, use glass tubes or rods 
for taking the paper out of the acid. Cotton treated in the same way be- 
comes soluble in a mixture of alcohol and ether, and is used by photog- 
raphers in making collodion. 



266 DIRECTIONS FOE EXPERIMENTS. 

33.-25. A special apparatus is necessary both for preparing and in- 
haling nitrous oxide safely. This consists of a glass retort— as shown in 
the cut— a wash-bottle, and, in addition, a gas-bag of from twenty to fifty 
gallons capacity for storing the gas, and a smaller bag of from three to five 
gallons, with a wide, wooden mouth-piece for inhalation. It is well to pass 
the gas through a large wash-bottle half full of caustic potash solution, 
and a second half full of H 2 0, as shown in Fig. 13, thence by a rubber tube 
directly into the large gas-bag. The utmost care should be taken both in 
preparing and administering this gas, as other oxides of nitrogen are liable 
to be present, especially if too high a heat is used. Before preparing the 
gas, pour into the bag a couple of gallons of H 2 0, by standing over which 
it will be purified in a few hours. When about to administer the gas, 
let the subject grasp his nose firmly between his thumb and forefinger; 
then, inserting the wooden mouth-piece, be careful that he does not inhale 
any of the external air, but takes full, deep breaths in and out of the gas- 
bag. Watch the eye of the subject, and notice the influence of the gas. 
Great care is necessary, and no one should ever inhale the gas who is not 
in good health, who is troubled with a rush of blood to the head, any lung 
or heart disease, or is of a plethoric habit. N 2 should never be admin- 
istered except when prepared and given by an experienced person. 

Repeat experiments 11, 12, and 13 with this gas. 

26. Half fill a test-tube with gas, over water. Close the tube under 
water firmly with the thumb, and then agitate the water and gas together. 
On removing the thumb under water, a considerable rush of water into the 
tube will occur, as the gas is soluble in about its own volume of cold water. 
By this circumstance the gas is easily distinguished from O. 

34.-27. When a jar is filled with the NO, it may be lifted out of the 
H 2 and inverted, when the N0 2 will pass off in red clouds. If the jar be left 
in the cistern, and one edge be lifted so as to admit a bubble of air, red 
fumes will fill the jar. By standing a moment, the water will absorb the 
red vapor. The process may be repeated several times with the remaining 
gas. The variation of this experiment, described in the note on page 34, 
will be found very interesting. The change of color produced by mixing 
nitric oxide with any gas containing free O, often affords a convenient 
means of detecting small quantities of O when present in admixture with 
other gases, such, for instance, as coal-gas. Hence NO may be used to dis- 
tinguish between O and N 2 0. 

28. Into a large jar inverted over water, introduce a measured quantity 
of NO, and exactly half as much pure O. The two combine to form N0 2 , 
which is soon dissolved in the water, and disappears. This illustrates Gray 
Lussac's law that gases combine in simple proportions by volume. 

35. — Ammonia is so much lighter than air, that it may be conveniently 
collected by upward displacement, as shown in Fig. 10. 

36.-29. If the bottle used for collecting the NH 3 be removed, and the 
flame of a Bunsen burner be applied to the jet of issuing gas, the NH 3 will 
not burn, but the gas-flame will be tinged with a pale yellow color. To 
show the burning of NH 3 in O, lead O into a wide-mouthed flask contain- 



DIRECTIONS FOR EXPERIMENTS. 



267 





ing strong aqua ammonia (Fig. 12). On gently heating, the ammonia, 
mixed with O, will come off, and may be lighted at the mouth of the flask. 

39. Hydrogen.— 30. For preparing H, the apparatus shown in Fig. 13 
is very convenient. The wash-bottle, d, is necessary only when it is desired 
to purify the gas for inhaling. A common junk-bottle, fitted with a cork 
and a glass tube, will answer for all ordinary experiments, but a "hydro- 
gen generator," as described below, is much more satisfactory. The Zn for 
making H should be granulated.* Water may be poured into the flask 
until the lower end of the funnel is covered, before adding the acid. The 
flow of gas may be regulated by additions of acid, as may be wanted. One 
part of acid to ten or twelve parts of water will liberate the gas rapidly. 
If too much H 2 SO € be added, the liquid is apt to froth over. 

A constant hydrogen generator can be readily made by taking two 
bottles with tubulature near 
the bottom, such as are sold 
by druggists for the "nasal 
douche, 1 ' and connecting 
them with a strong rubber 
tube. One is fitted with a 
cork and delivery tube pro- 
vided with a stop-cock. In 
this bottle is placed a layer 
of pebbles or broken glass, 
and upon this a quantity of 
zinc scraps. In the other 
bottle is dilute H 2 S0 4 . On 
opening the stop-cock, the 
acid comes in contact with 
the zinc, and H is evolved. 
As soon as the stop-cock is 
closed, the pressure of the 

gas drives the acid back into the other bottle. The same kind of apparatus 
may be employed for generating C0 2 or H 2 S. 

A hydrogen generator, similar in principle to the Dobereiner lamp 
(Fig. 19), can be made by cutting off the bottom of a tall and narrow bottle, 
filling it with zinc scraps, and closing at the lower end with a perforated 
rubber cork, and at the upper end with a perforated cork carrying a brass 
or glass tube and stop-cock. Place it upright in a jar of dilute sulphuric 
acid. 

In experimenting with H, great care must be used not to ignite the jet 
of gas until all the common air has passed out of the flask ; otherwise a 
severe explosion will ensue.t It is a safe precaution to test the gas by 

* This is easily done by melting the Zn in an iron ladle, and pouring the metal 
slowlv from a little height into a basin of water. 

•T Always wrap a cloth around the H generator when you ignite the gas, as an 
additional precaution. 



ZINC 




f PEBBLES^ 



268 DIRECTIONS FOR EXPERIMENTS. 

passing it in bubbles up through H 2 0, and igniting them at the surface ; 
the force of the combustion will indicate if there be any danger. H must 
not be kept in bags for any great length of time, as the air will gradually 
force itself in, and the gas will partly pass out, thus forming an explosive 
mixture which it is dangerous to ignite. 

31. The gases may be mixed in the following manner : Pit a good cork 
into the neck of a large jar, and pass through it a tube five centimeters 
long. Bind a short piece of rubber tubing firmly to the tube, and close this 
elastic tube with a small pinch-cock.* Fill the jar with water over the 
pneumatic tub. Fill a small jar, which will hold about half a liter, with O, 
and transfer it, as shown in Fig. 18, to the large jar. Fill the same jar. 
with H, and transfer it to the large jar. Repeat the operation with the H, 
so as to obtain in the larger jar a mixture of half a liter of O and one liter 
of H. Having previously softened a thin bladder by soaking it in water, 
tie into the neck of it a glass tube five centimeters long ; then adjust to 
the projecting portion a piece of rubber tubing provided with another 
pinch-cock. Press the air out of the bladder; connect the two pieces of 
rubber tube by means of a short piece of glass tubing; depress the jar in 
the pneumatic tub, and then open each pinch-cock. The gas will now pass 
into the bladder,— if it does not, press the jar deeper into the water. Close 
both pinch-cocks, and remove the bladder. Now place the end of the tube 
attached to the bladder under some soap-suds, and blow a mass of soap- 
bubbles by squeezing the bladder. Remove the bladder to a distance, and 
then apply a light to the bubbles. A loud explosion will immediately 
follow. 

32. A clay tobacco-pipe may be attached to the gas-bag by means of a 
bit of rubber tubing. Dip the pipe-bowl into the soap-suds, and, lifting it 
out, blow a bubble with the mixed gases, and then detach it by a quick 
motion. When the gas-bag is removed, ignite the bubble, which will ex- 
plode sharply. If bubbles be blown with H alone, they will rapidly rise, 
and, if out-of-doors, will float to a great distance.t 

33. H is the lightest known substance. Fill two bottles with the gas, 
suspend one inverted from the ring of the retort-holder, and place the 
other right side up on the table. In a few minutes the upright cylinder 
will be found to contain little or no H, while the inverted bottle is nearly 
full. 

34. Suspend an inverted beaker glass from the end of the scale beam 
(Fig. 27). Balance it carefully; then fill it with H gas. It will be found 
much lighter than before. 

35. Take a small porous cup, such as is used for electrical batteries. Fit 
a cork to it, and pass a long glass tube through the cork. Cover the cork 

* Small pinch-cocks are sold for this purpose. They are cheaper than stop-cocks, and 
answer every purpose. In lieu of these, common spring clothes-pins may be used. 

+ If one has a large rubber gas-bag, with stop-cock and rubber tubing, and a glass 
receiver fitted with a stop-cock on top, these may be attached, and the gases measured in 
the receiver, and then passed directly into the bag. Such apparatus, though convenient, 
is not necessary to illustrate the properties of the gases. 



DIRECTIONS FOR EXPERIMENTS. 



269 



with, plaster of Paris. Place tlie tube upright, with its lower end dipping 
into a colored liquid (CuS0 4 + NH 4 0H). Hold a jar of H over the porous 
cup. The H enters the cup, driving the air out of the lower end of the 
tube. Remove the jar, and the liquid will rise several inches in the tube. 
(See "Physics," p. 50.) 

36. A substitute for spongy platinum in the experiments with hydrogen 
gas: Make a cylinder of pumice-stone, three eighths of an inch in 
diameter. With a fine saw, cut it into disks about one twentieth of an 
inch thick. Soak these for some time in a strong solution of bichloride of 
platinum in alcohol, and then as long in an alcoholic solution of sal- 
ammoniac. After being once thoroughly ignited, these disks will inflame a 
jet of hydrogen. 

45.-37. The analysis of water can be readily performed as follows: 
Take a wide bottle (the height is unimportant), and cut it off about two 
and one half inches below the neck, by making a scratch with a three- 
cornered file, and then applying near the scratch a very hot piece of wire or 
glass, or a small blow-pipe flame. The crack will follow the flame slowly 
around the bottle. Take two strips of platinum foil, and put one on each 
side of a well-fitting cork, so that one end extends into the bottle, the other 
outside of the neck. Support the apparatus inverted upon a ring of the re- 
tort stand, and fill nearly full of water acidulated with H Q S0 4 . Connect 
the strips of Pt with the poles of a battery of two bichromate or Bunsen 
cells. Bubbles of gas at once appear, and can be collected in inverted 
test-tubes, and tested. Instead of a bottle-neck, a broken funnel may be 
employed. (See "Physics," p. 237.) 

38. The synthesis of water may be shown, and also its composition by 
weight, by passing dry H over dry CuO. The CuO is placed in a bulb-tube 




r^ 







of hard glass C, and weighed. The tube Z>, filled with pieces of fused cal- 
cium chloride, is also weighed. The H generated in A is dried by CaCl 2 at 
-S, and passes over the CuO at C. When the air has all been expelled, heat 
the CuO until it has a bright red color. Allow the H to pass through until 
the tube C is cold. Take the apparatus apart, and weigh the tube C; it 



270 



DIRECTIONS FOR EXPERIMENTS. 



will have decreased in weight by a quantity equal to that of the O expelled. 
Weigh the tube D. It has increased by a quantity equal to that of the 
water formed. If C has lost 16 grams in weight, D will have increased 18 
grams in weight, showing that 16 parts of O will form 18 parts of water, 
by taking up 2 parts of H. 

39. Burning H in O. Attach a CaCl a drying tube to a hydrogen 
generator, and to this a glass tube bent twice 
at right angles, and then turned up at the end, 
as shown in the figure. Take a small piece of 
Pt foil, and roll it around a darning-needle so 
as to form a small tube. Soften the end of the 
glass tube, and slip this little tube into it while 
hot, then hold them in the flame until the glass 
settles down against the Pt on all sides. When 
the air has all been expelled 
from the generator, throw a 
towel over it, and ignite the 
H, then bring it into a 
broad jar of O. The heat is 
very intense, hence the need 
of a Pt tip. 

40. Burning O in H. To 
show the reverse experiment 
of burning O in H or illu- 
minating gas, take a large 
lamp chimney, and fit a 
cork in each end. In the 
upper cork, insert a glass tube drawn out to a jet D. 
In the lower end, insert a bent glass tube A, and a 
metal tube (7, made by rolling up a strip of sheet iron 
or brass. Eit a cork to the metal tube, and pass a glass 
tube with a Pt tip on it through this cork (B). Attach the tube A to an H 
generator, and when the whole apparatus is full of H, ignite it at D and C. 
Connect B with a gasometer or bladder of O, then quickly insert the cork 
into the opening C, so as to extinguish the flame there. !Let the O pass in 
slowly. The O will be seen to burn in an atmosphere of H. Cut off the 
supply of O, and extinguish all flames before removing the supply of H, 
to avoid an explosion. 

48. — 41. Take some fresh crystals of sodium sulphate ; let them lie 
exposed on a piece of blotting-paper for two or three days. They will 
gradually lose their water and crumble down, or effloresce into a white pow- 
der. Common washing soda will do the same. 

42. Take two four-ounce bottles, and put in each a teaspoonful of white 
sugar. Pill one bottle nearly full of pure rain or distilled water, the other 
with impure water. Cork them, and let them stand a few days ; in one 
bottle will be seen a fungoid growth, resembling fuzz or lint ; the water in 
the other bottle remains clear. (Note, p. 194.) The sporules or germs that 





DIRECTIONS FOR EXPERIMENTS. 



271 



fall into the water find suitable nutriment for their development in one 
case, but not in the other. Any well or spring water in which this change takes 
place is unfit to drink. (Page 48, note.) 

43. Select a thin, porcelain dish which will hold 60 or 80 cub. cm. ; 
place it in one pan of the balance, and trim a piece of lead until, when 
placed in the other scale-pan, it will counterpoise the dish. Measure a 
quarter of a liter of spring-water, and pour some of it into the weighed 
dish ; place it over a very small gas-flame, so as to evaporate the H 2 gently, 
without allowing it to boil ; add the rest of the H 2 from time to time until 
it has completely evaporated. Dry the salts thus obtained, and weigh what 
is left as accurately as you can. By multiplying this quantity by 4, you 
will obtain the amount of soluble solid substances per liter which that par- 
ticular specimen of water contained. This is the basis of the plan which, 
with many additional precautions, is adopted for determining the quantity 
of salts in the process of analyzing waters to be used for drinking or manu- 
facturing purposes. 

50.— 44. The expansion of water in freezing may be shown thus : Fill 
a common round-shouldered bottle with ice-water ; cork tightly, and place 
in a freezing mixture (broken ice and salt) ; or, if it is a cold winter's day, 
out-of-doors. The ice in crystallizing will either break the bottle, or push 
out the cork, which will be found frozen on to the end of a stem of ice. 
If the bottle be broken, it will be seen that it is completely filled with solid 
ice. 

55. Carbon.— Small paste-diamonds may be obtained of a jeweler, to 
illustrate the forms of cutting the diamond. 

56.-45. Take a glass. cylinder open at both ends, and 
suspend near the top an inverted funnel which fits nicely 
into the cylinder. Place a bit of camphor burning on a 
small dish below it, so that the smoke passes up into the 
funnel. When a considerable quantity of lamp-black has 
formed on the sides of the cylinder and funnel, extinguish 
the flame and remove the lamp. Then slowly lower the 
funnel, the edge of which will scrape the lamp-black from 
the sides of the vessel, in the same manner that it is done 
by manufacturers in making lamp-black for the market. 

62.-46. Place a filtering-paper* in the glass funnel, 
and in it two ounces of bone-black or finely powdered 
charcoal. Filter through it water colored with ink, litmus, 
or any other impurities. In pouring the liquid into the filter, hold a glass 
rod against the edge of the pouring vessel, so as to direct the stream into 
the funnel. The funnel may be placed in the nozzle of a bottle, but must 
not fit closely. A bit of wood or a thread inserted between the stem of 




* In order to prepare this filter, fold a square of filter-paper, as shown in the figure 
on next page, first into half, and then again into a quarter of its first size {b) ; cut off the 
edges in the direction of the dotted line shown in the left-hand figure (a), open out the 
folded paper (c), and drop it into a funnel a little larger than the paper-cone. 



272 



DIRECTIONS FOR EXPERIMENTS. 




the funnel and the nozzle will leave an opening sufficient for the egress 
of the air. 

47. Slip a piece of freshly-burned charcoal under the edge of a long tube 
previously filled with dry ammonia gas,* and standing over Hg. The char- 
coal will quickly absorb the NH 3 ; the whole of the gas, if pure, will dis- 
appear, and the Hg will fill the tube. 

48. Weigh a piece of freshly-burned charcoal as soon as it is cold ; leave 
it exposed to the air for twenty-four hours, and weigh it again ; it will be 
found to be heavier. Place the charcoal in a glass tube, and heat it over 
a lamp ; moisture will be driven off, and will become condensed on the cold 
sides of the tube. 

49. Shake up with a little powdered charcoal some stagnant water which 
has been kept till it smells offensively. In an hour it will have lost all its 
disagreeable odor. 

50. Mix in a mortar twenty grams of litharge with forty grams of NaCl 
and one gram of powdered charcoal ; cover with a little more salt, and place 
the mixture in a small clay crucible ; heat it to bright redness in the fire. 
When the mixture is melted, take the crucible out of the fire and let it 
cool. When quite cold, break the crucible, and a bead of Pb will be found 
at the bottom, under the melted salt, the C having taken the O from the 
PbO. 

63.— 51. Break some marble into small bits ; place them carefully in the 
evolution-flask, and, inserting the cork and tube, pour in HC1 slowly. The 
gas, on account of its weight, may be passed directly into a bottle or jar, 
and collected by downward displacement. 

52. Lower a lighted candle into a jar of the gas, or, placing the candle 
in an empty jar, pour the gas into the jar, as if it were water. 

53. Test the gas with moistened blue litmus-paper. 

64.-54. In a pint of water place a piece of lime as large as an egg ; let it 
stand over night ; pour off the clear liquid ; it is lime-water. Place a little 
in a tumbler and pass a current of C0 2 from the evolution-flask into the 
liquid. It becomes milky, and then, after a time, clear. If the clear liquid 
be boiled, C0 2 is driven off, and the lime is again precipitated. This is a 



* The gas may be dried by passing it through a tube filled with pieces of lime. 



DIRECTIONS FOR EXPERIMENTS. 273 

good illustration of the formation of hard water, and of the way in which 
it produces an incrustation when boiled. (See p. 49.) 

55. Repeat the experiment by breathing from the lungs through a tube 
into the lime-water. The last portions of air exhaled will be found to be 
most highly charged with C0 2 . 

Or, the formation of carbon dioxide in the lungs may be shown by an 
experiment of Earaday's. Eit an open-mouthed receiver with a cork, through 
which passes a small bit of glass tubing. The receiver is then placed in a 
basin of water. Expelling the air from his lungs, the experimenter inhales 
the air in the receiver through the tube. The water in the basin rises in 
the receiver, and shows how fast and when the air is exhausted. Breathing 
back the air from the lungs into the receiver again, the water is expelled, 
and the lighted taper will test the presence of the carbon dioxide. Before 
testing, the air may be breathed back and forward two or three times, until 
it becomes unpleasant. The rise and fall of the water in the jar is a pleasant 
and instructive addition to the experiment. 

65.-56. Arrange little wax-tapers in a wooden or pasteboard trough, as 
on page 65. Light them, and then pour in at the top a bottle of carbon 
dioxide gas. If the proper slant is given to the trough, all the candles will 
be extinguished. (Eig. 26.) 

57. Balance a beaker on a delicate pair of scales, or in any simple man- 
ner one's ingenuity may suggest. Empty into it a large jar of C0 2 , and it 
will quickly descend. (Eig. 27.) 

66. — 58. Twist a wire around the neck of a small, wide-mouthed vial, to 
answer as a bucket. Lower it by the wire into a jar of C0 2 , our ideal well 
foul with the gas. Raise it again, and test for the C0 2 by means of a 
lighted match. The bucket will be found full of the gas. 

70.— 59. Carefully heat in a flask fitted with a cork and gas-delivery 
tube (see Eig. 8), 5 grams of potassium ferrocyanide and 50 cc. of concen- 
trated H 2 S0 4 . CO will come off freely, and will burn with a bluish flame. 
Be careful not to inhale the gas. 

60. Place a few crystals of oxalic acid (C 2 H 2 4 ) in a test-tube, pour on 
enough oil of vitriol to cover them, and then heat gently. Both CO and 
CO 2 will be evolved. On applying a flame to the open end of the tube, the 
CO will take fire and burn with a blue flame. To separate the two gases, 
pass them through a solution of KOH, which will remove the C0 2 , and the 
CO can then be collected over water. 

7 | .—61. CH 4 may be made by heating in a test-tube 2 grams of sodium 
acetate, 8 grams of caustic soda, and 2 grams of powdered quicklime. 

72.-62. Introduce into a retort which will hold a liter, 10 cc. of alco- 
hol and 60 cc. of strong sulphuric acid. Heat the mixture, and collect the 
gas over water ; continue the experiment until the mass blackens and swells 
up considerably. The product consists at first chiefly of oleflant gas, mixed 
with ether-vapor; but toward the end it becomes mingled with S0 2 . Pass 
it through a solution of potash, using a wash-bottle as shown in Eig. 13, 
and then collect in the gas-bag. Eit a piece of glass tubing, drawn to a 
fine point at one end, to the stop-cock of the gas-bag, by means of a bit of 



274 DIRECTIONS FOR experiments. 

the rubber tubing. On turning the stop-cock and forcing out the gas, it 
may be ignited, when it will burn with a clear white light. 

63. Mix C 2 H 4 with three times its bulk of O and explode in soap-bub- 
bles. Great care must be taken not to let the light approach the gas-bag 
containing the mixture. 

64. Get a bit of bituminous coal about the size of a walnut. Pound it 
small, almost into dust. Pill an ordinary tobacco-pipe (one with a long stem 
is preferable) nearly full of the pounded coal, packing it down closely with 
your thumb. On the top press a disk of metal or a copper coin, and cover 
with a layer of plaster of Paris or some tough clay, reduced to the con- 
sistency of putty by being tempered with a little water. Heat the bowl of 
the pipe strongly, and a combustible gas will come out of the stem, which 
should now be held in a nearly vertical position. "When no more gas is 
given off, and the jet of flame goes out, remove the clay or plaster cover- 
ing. The residue in the bowl is coke. 

65. Place some bits of pine wood in a glass retort provided with a per- 
forated cork and delivery-tube. Connect this with an empty wash-bottle. 
On heating the retort, gas is given off, tar collects in the wash-bottle and 
charcoal remains in the retort. The charcoal used for making gunpowder 
is prepared in this way in large iron cylinders. 

74.-66. Pit a cork to a small test-tube. Take out the cork, and pass 
through it a bit of glass tubing drawn to a fine point at one end, so as to 
act as a gas-burner. Place in the tube about two grams of mercury cyanide ; 
replace the cork, and heat over a spirit-lamp. The test-tube may be sup- 
ported by a strip of thick paper twisted around it at the top. Move the 
tube to and fro through the flame at first, until it becomes fully heated ; 
hold the tube inclined and not perpendicular, letting the flame strike the 
side rather than the bottom. When the gas begins to come off, it may be 
ignited. 

67. To show the formation of potassium cyanide from a nitrogenous 
body : Drop into a perfectly dry test-tube a bit of nitrogenous substance 
and a small piece of freshly cut K or Na. Heat carefully until it melts 
and a flash of light is seen. When cold, break the tube, throw the fused 
mass into a clean test-tube, and make the test for KCy as given below. 

68. To test for the presence of potassium cyanide : Add to a solution of 
the suspected substance a few drops of solution of sulphate of iron and a 
slight excess of potash. Shake the precipitate a few moments with air in 
the tube, and add an excess of hydrochloric acid, when a blue precipitate, 
or a decided blue or green color pervading the liquid, will indicate the 
presence of a cyanide. Prussian blue is produced by this process. 

8 I —69. The compound blow-pipe with gasometers, as shown in Pig. 39, 
is a serviceable apparatus. If gas-bags are used, the one for H should be 
twice the size of the one for O. A board should be laid on each bag, upon 
which weights may be placed, when ready for use, so as to force out the 
gas steadily. Always ignite the H first, and then turn on the O slowly 
until the best effect is produced. All the metals burn in the blow-pipe 
flame with their characteristic colors. Narrow slips should be prepared for 



DIRECTIONS FOR EXPERIMENTS. 275 

this purpose. A cup for holding the chalk is necessary to show the lime- 
light. A piece of hard lime, whittled to about the size of a pencil, may be 
held in the flame to illustrate the principle. 

89.— 70. To a small gas- jar fit a good cork, through which pass a test- 
tube as shown in Fig. 43. Place the jar in a large beaker glass or open- 
mouthed bottle, filled with spring water, which has been mixed with a 
fourth of its bulk of a solution of carbonic acid in water. Fill the tube 
with water, and place it in the neck of the jar, having introduced a few 
sprigs of mint or the leafy branches of any succulent plant ; then expose 
for an hour or two in direct sunshine. Bubbles of gas will be seen studding 
the leaves; and on shaking the jar they will become detached, and will 
rise into the test-tube. After a time the cork and tube may be withdrawn, 
keeping the mouth of the tube beneath the surface of the water; then 
close it with the thumb, turn the tube mouth upward, and test the gas 
with a glowing splinter. The wood will burst into a blaze, showing that the 
gas consists mainly of O. 

92. Chlorine.— 71. Put in the generating flask (see Fig. 44) a mixture 
of equal parts of NaCl and Mn0 2 ; insert the cork with its tubes, and pour 
in through the funnel tube sulphuric acid which has been diluted with an 
equal weight of water. On gently heating, the gas will come off abun- 
dantly, and may be collected by downward displacement in tall jars (see Ex. 
51). The gas may be dried by passing it through a wash-bottle containing 
strong H 2 SO*. 

93.-72. Plunge a lighted candle into the gas : it will burn feebly, with 
a red, smoky flame. (Fig. 45.) 

73. Place a piece of dry phosphorus in a copper deflagrating spoon ; in- 
troduce it into a bottle of CI : the phosphorus will take fire and burn, while 
suffocating fumes of phosphoric chloride (PC1 5 ) are formed. 

74. Dip a strip of blotting-paper into oil of turpentine ; plunge it into a 
jar of CI : it will immediately burst into flame, while a dense black smoke 
is given off. (Fig. 46.) 

75. Powder some metallic Sb finely in a mortar, and sprinkle into a jar 
of CI : it will take fire as it falls, giving out fumes of antimony chloride 
(SbCl 5 ), which are very irritating. 

94.-^6. Fill a flask with water and lead CI into it until no more dis- 
solves. Withdraw the tube through which the CI has entered ; fill the flask 
to its mouth with chlorine water ; close it with a cork in which is a small, 
short glass tube ; and support it in an inverted position, so that the end of 
the glass tube is below the surface of water contained in a beaker. Place 
in a window where the direct sunlight will fall upon it. A bubble of gas 
will soon appear at the top of the inverted flask, and will go on increasing 
in size from day to day until all the greenish color has disappeared from 
the water. Then transfer the gas to a test-tube (see Fig. 18) and test it 
with a spark on a splinter of wood. The gas is thus proved to be O. The 
water in the flask contains HC1, as may be shown by adding a few drops 
of silver nitrate solution (see p. 97). 

77. Pour a little boiling water upon some chips of logwood, so as to 



276 DIKECTIONS FOE experiments. 

obtain a deep red liquid ; add some of the solution of CI, and the red color 
will be discharged. 

95.-78. Write a few words with ordinary ink on a printed card and 
put it in moist CI or in chlorine water. The writing will be bleached, 
while the printed words are unchanged. 

79. Print the word Proteus on a large card, first with the iodide-of- 
potassium-starch solution (note, p. 101), and second with a solution of 
indigo. The former will be white and almost invisible, the latter blue. 
Then paint the words (using a camel's hair brush) with a solution of chlo- 
rine. The first line will turn blue and the second white, thus just reversing 
their color. 

80. Bleach some colored calico by putting it into water with which a 
little bleaching powder has been mixed. The action is hastened by adding 
a little vinegar or a few drops of any dilute acid. 

96.— 81. Burn H in CI, as shown in experiment of burning H in O. (Ex. 40.) 

82. "Wrap a soda-water bottle in a towel ; fill it with water, and invert 
it in the pneumatic tub. Introduce a glass funnel into the neck, and 
having filled a jar of 100 cc. capacity with CI, pass the gas into the bottle. 
Pill the same jar with H, and empty into the same bottle ; withdraw the 
funnel, close the neck with the palm of the hand, lift the bottle out of the 
water-bath, give it a shake to mix the gases, and apply a light. A sharp 
explosion will immediately follow, and gaseous HC1 be formed. Equal 
measures of H and CI unite in this way, and the gas produced occupies the 
same bulk that its components did when separate. Sunlight will also cause' 
the explosion of a mixture of CI and H. 

83. To prepare HC1 put some common salt in the generating flask 
(Pig. 47), and pour through the funnel tube about twice its weight of 
strong H 2 S0 4 . A solution of the gas — ordinary hydrochloric acid — is 
obtained by leading it through water, as shown in the cut. The gas itself 
may be collected for experiment by downward displacement, as in the case 
of CI. 

The gas may also be obtained by gently heating concentrated hydro- 
chloric acid. In this case it should be dried by leading it through strong 
H 2 S0 4 in a wash-bottle, before collecting it for experiment. 

84. A candle lowered into a jar of HC1 gas is extinguished. 

85. Pill two jars of the same size, the one with HC1 gas, the other with 
NHj. Bring them mouth to mouth and remove the glass plates by which 
they were closed. The two gases immediately combine, forming a white 
cloud of ammonium chloride. 

86. Dilute a little HC1 with six or eight times its bulk of water, and 
add caustic soda cautiously, until the liquid is neutral, and neither reddens 
blue litmus nor restores the blue to red litmus-paper. Pour the liquid into 
a basin, and evaporate it slowly; crystals of Nad will be deposited in 
cubes. 

87. Boil HC1 in a test-tube with fragments of gold-leaf, or a bit of 
platinum wire ; they will not be dissolved. Now add a drop or two of 
HNO3 ; a yellow solution will be formed. 



DIRECTIONS FOR EXPERIMENTS. 277 

88. Mil a test-tube nearly full of pure rain or snow water, and add a 
drop or two of the nitrate of silver solution. A drop of HC1 will cause a 
cloudy, white precipitate.* 

100. Bromine and Iodine.— 89. Pour a little strong H 2 S0 4 onto a few 
crystals of potassium bromide in a test-tube. Heavy red vapor of Br will 
fill the tube. 

90. Dissolve in a little water in a test-tube a crystal of potassium bro- 
mide ; add a little chlorine water. Br is set free, and the solution becomes 
brownish in color; now add a few drops of chloroform, and shake 
thoroughly. When the chloroform settles to the bottom, it is colored 
yellow by the Br it has dissolved. If dilute starch paste is added instead 
of the chloroform, it also becomes yellow. 

91. Repeat experiments 89 and 90 with potassium iodide instead of 
potassium bromide. Violet vapor of iodine will be given off in the first; 
the chloroform will acquire a beautiful violet color, and the starch paste 
will become dark blue. 

I 03. Sulphur. — 92. Melt a quantity of S, either the flowers or brim- 
stone, in a test-tube. If heated carefully and uniformly, the liquid S is at 
first thin and amber-colored ; then becomes dark, and so thick that at a 
certain point it will not run from the inverted test-tube ; and finally, at a 
higher temperature, regains its fluidity and boils, giving off a deep red 
vapor, which readily burns. Pour the liquid S into water. It forms an 
elastic gum, which slowly hardens and becomes brittle. 

93. Pill a clay crucible or a cup with brimstone, and melt it with a 
gentle heat. Set it aside to cool. When a crust has formed on top, break 
it, and pour out the liquid contents. If the cup be broken when cold, the 
interior will be found filled with long amber-colored transparent crystals 
of S, which after a time become opaque and yellow. 

94. Pulverize some brimstone, and put in a test-tube and cover with 
CS.,. Put the tube in warm water until the S dissolves, then cork it tightly, 
or, better, pour the solution onto a watch-glass under a bell- jar, and let it 
stand until crystals separate. They have a different form from those 
obtained from fusion. The more slowly they separate, the larger they 
will be. 

95. Put a piece of S in a test-tube, and above it some copper turnings 
or scraps. Heat the sulphur until it boils. The Cu burns brightly in the 
vapor of S. Pe and Pb will also burn in S vapor. 

I 04.— 96. Dissolve in a little water a crystal of potassium perman- 
ganate. On leading S0 2 into the solution, or adding a little sulphurous 
acid, the solution becomes colorless. 

I 05.— 97. Mix a little sulphurous acid and chlorine water. The presence 
of HC1 and H 2 S0 4 can be shown by the silver nitrate and barium chloride 
tests (pages 97 and 109). 

I 08.— 98- The method of making H 2 S0 4 may be finely illustrated by 

* Well water, which gives a considerable precipitate with AgN0 3 , is usually unfit to 
drink, owing to sewage contamination. 



278 DIRECTIONS FOR EXPERIMENTS. 

means of the apparatus shown in Pig. 51. The large glass globe takes the 
place of the leaden chambers. Of the two flasks at the left, one contains 
strips of Cu and strong H 2 S0 4 , for the production of S0 2 (see p. 104) ; the 
other contains water, to furnish a supply of steam ; NO is supplied from 
the generator at the right (see p. 33); air is introduced from a small 
bellows, or the mouth, through the long rubber tube, while the straight, 
upright glass tube acts as a chimney for the escape of waste gases. If the 
supplies of NO and air are cut off after the globe is filled with ruddy 
fumes, the gases filling the globe will soon become nearly or quite colorless, 
from the reduction of N0 2 to NO ; on introducing a little air, the red color 
reappears. 

99. Pour a little strong sulphuric acid into a test-tube. Place a splinter 
of wood in it ; the wood will be blackened in a few minutes. Pour 1 cc. of 
strong H 2 S0 4 into a tube containing 3 or 4 cc. of water ; considerable heat 
will be felt to attend the mixture.* Take a little of this diluted acid, and, 
with a feather dipped into it, trace a few letters upon writing-paper. Hold 
the paper near the fire : the water will evaporate, leaving the acid behind ; 
this will soon blacken the paper. 

100. Mix 4 oz. H 2 S0 4 and 1 oz. pounded ice or snow. Stir it with a 
test-tube containing a little ether ; the ether soon boils. 

101. Mix 1 oz. H 2 SO* with 4 oz. snow or pounded ice, and stir it with 
a test-tube containing cold water; the water soon freezes. The vessel in 
which the experiment is performed usually freezes fast to the table, so that 
it is well to set in on a plate or small board. 

102. Dissolve some sugar in a very little water, so as to form a thick 
syrup. Put it in a tall beaker, and pour on strong H 2 S0 4 until it begins to 
swell up and blacken. The H 2 S0 4 removes the H 2 from the sugar, leaving 
only C behind. 

I 09-— 103. Place in an evolution flask (J., Pig. 52) a few lumps of fer- 
rous sulphide, and add some dilute H 2 S0 4 . Dead the H 2 S gas through a 
solution of copper sulphate in i?, one of tartar emetic in (7, one of arsenic in 
D, one of zinc sulphate in E, and finally into water in the beaker. Pre- 
cipitates—sulphides of the metals— will be produced, brownish-black in B, 
orange in (7, yellow in i>, and white in E. (See chapter on "Qualitative 
Analysis.") 

I I O.— 104. Place a few drops of the disulphide in each of four test- 
tubes. To one add a little powdered sulphur, to a second a few minute 
scales of iodine, to a third a fragment of phosphorus, and to a fourth a few 
drops of water. Notice the beautiful color produced by the iodine; the 
solution of the sulphur and the phosphorus ; the insolubility of the liquid 
in water ; and also its refractive power. 

105. The experiment of burning P under water may be easily shown by 
throwing a piece of P into a glass of hot water. It melts, and looks like a 
thick oil under the water. A fine stream of O gas may then be passed 
through a glass tube down to the P, which burns brightly under water. 

* In mixing H 2 S0 4 and H 2 0, always pour the acid into the water. 






DIRECTIONS FOR EXPERIMENTS. 279 

| | 4. Phosphorus.— 106. Dissolve 1 or 2 decigrams of phosphorus in 
2 cc. of carbon disulphide in a test-tube ; pour a little of the solution 
upon a piece of filtering-paper, and allow it to dry. The phosphorus 
will be left in a finely-divided form, and will set fire to the paper in a few 
minutes. 

107. Place a bit of phosphorus in a solution of silver nitrate. In the 
course of a day or two, it will be covered with brilliant crystals of reduced 
silver. Repeat with CuS0 4 solution. 

I | 6.— 108. To prepare hydrogen phosphide, place in the flask («, Pig. 54) 
a strong solution of caustic potash and a few small pieces of phosphorus. 
The addition of a little ether will serve to expel the air, and prevent the 
danger of an explosion. Regular smoke-rings will be formed only in per- 
fectly still air. 

I 19". Arsenic— 109. Compounds of As, when heated on charcoal, give 
off a garlic odor. 

110. Add a few drops of a solution of arsenic trioxide to 200 or 300 cc. 
of water, a|id then 3 or 4 cc. of HC1 ; place in the liquid two or three 
slips of bright copper foil, and boil the whole for a few minutes : the cop- 
per foil will become coated with a steel-gray film. Part of the Cu becomes 
dissolved and displaces the arsenic, which is thrown down on the undis- 
solved portion. Pour off the water, dry the Cu on blotting-paper, and heat 
the foil in a tube, sealed at one end. The arsenic will sublime, condensing 
in minute octahedra on the cold sides of the tube. This is Reinsch?s test for 
arsenic. 

I 22. -Boron. — 111. Make a small round loop at the end of a thin 
platinum wire. Dip the hot loop into powdered borax, and heat the ad- 
hering salt until it melts to a clear, transparent bead. Moistened with a 
solution of cobalt nitrate and heated, the bead becomes blue ; with man- 
ganese dioxide, or any manganese salt, the clear bead changes on heating 
to an amethyst color. 

112. Add to a solution of boric acid (or borax and H 2 S0 4 ), in a small 
dish, a little alcohol. Set fire to the alcohol, and, as it burns, stir the solu- 
tion with a glass rod. The flame is tinged green. 

113. A similar green coloration is obtained by bringing a little boric 
acid (or borax moistened with H 2 S0 4 ) into the Bunsen flame on a platinum 
wire, which has first been dipped in glycerin. 

Silicon, — 114. Grind in the mortar 3 or 4 grams of fluor spar, and mix 
with an equal weight of powdered glass or sand. Introduce it into a flask 
previously fitted with a sound cork and a tube, as in the figure. Pour upon 
the mixture 30 grams of strong H 2 S0 4 , insert the cork and tube, and apply 
a gentle heat : a densely fuming gas is disengaged, consisting of silicic 
fluoride (SiF J. This gas must not be inhaled, as it is very irritating. Pass 
it into a glass of H 2 0, having sufficient Hg at the bottom to cover the 
mouth of the delivery-tube. Each bubble of gas, as it rises, is coated with 
a white film of hydrated silica, while a solution of hydrofluosilicic acid 
(2HF,SiFJ is formed. The deposit of silica would clog the tube if it were 
not for the Hg ; hence the tube must be kept dry, which is best accom- 



280 



DIRECTIONS FOR EXPERIMENTS. 




plished by placing it in position in the Hg, then pouring water carefully 

into the glass on the Hg. 
Miter the solution, and pre- 
serve it as a test for Ba and 
K. 

115. Grind a little glass 
to a fine powder in a mortar ; 
place it on a piece of moist- 
ened red litmus-paper; suffi- 
cient alkali will be dissolved 
by the water to tinge the 
paper blue. 

116. Mix a little fine sand 
with KNO a and Na^COg, and 
heat strongly on a strip of 
Pt foil for five minutes. 
"When cold, it will dissolve 
in H 2 0. 

117. Take some of the 
silica obtained in the experi- 
ment of making 2HF,SiI\, 
and put it in a strong so- 
lution of KOH, and boil. It will dissolve.* 

118. Take four glass cylinders, five inches high, and pour into each about 
1 oz. of ordinary water-glass and 4 oz. of water. Drop into one a few 
crystals of iron sulphate, into another some crystals of blue vitriol, into the 
third white vitriol, into the fourth a crystal of each. Let them stand 
quietly for twenty-four hours. In the first green fibers will be seen, re- 
sembling very closely a growing plant ; blue and white ones will appear in 
the others. If closely corked, they can be kept for weeks. 

119. Pour 1 oz. of water-glass into a capsule, and pour on it half as much 
H2SO4, taking care that the two do not mix. Pour immediately, but 
slowly, into a second capsule ; the silica separates in long tubes resembling 
stalactites. 

I 28. Potassium.— 120. Place 30 grams of pearlash in a half -liter bottle, 
and dissolve it in 250 cc. of water. Shake 20 grams of quicklime with five 
or six times its bulk of water, and add the pasty mixture (about 120 cc. 
in bulk) to the boiling solution of pearlash. Agitate the mixture, and let 
it stand till it is clear. Pour off a portion of the liquid : it is a solution of 
caustic potash. Add to it some HC1 : no effervescence will occur. Agitate 
a tablespoonful of olive-oil in a small vial with 3 or 4 cc. of the caustic 
solution diluted with ten times its bulk of water : a milky-looking liquid 
will be formed, which is the first stage in the making of soap. 



* The infusorial silica, sold under the name of electro-silicon, will dissolve in KOH 
in the same manner. A basic silicate, known as "water-glass," or "soluble glass," is 
prepared in this way. 



DIRECTION'S FOR EXPERIMENTS. 281 

121 Burn some dry brushwood ; collect the ash, wash it with five or six 
times its bulk of water, and filter. Test the solution with a piece of red- 
dened litmus-paper, which will become blue. Evaporate the solution to 
dryness in a small porcelain dish. If the dry mass be left exposed to the 
air for a few hours, it will become moist. The potassium carbonate, of 
which it chiefly consists, attracts moisture rapidly, and deliquesces. To a 
portion of the salt, add a few drops of HC1 : brisk effervescence occurs. 

I 29.— 122. Pulverize finely nitrate of potash and chloride of ammonium, 
five parts of each, and mix with sixteen parts of water. The temperature 
of the mixture will be reduced so low that, if a test-tube with a little 
water in it be used to stir it, the water in the tube will be converted 
into ice. 

| 3 ( .—123. Into a dilute solution of KOH, lead CI gas until no more is 
absorbed. Evaporate the solution until crystals are formed. These consist 
of potassium chlorate, KC10 3 . Separate them from the liquid, and dry by 
pressing between folds of filter paper. 

124. To demonstrate the oxidizing power of KC10 3 : Put into the mortar 
as much potassium chlorate as will lie upon the point of a knife-blade, and 
half as much sulphur. Cover the mortar with a sheet of writing-paper, 
having a hole cut in it just large enough for the handle of the pestle to 
pass through. "When the two substances have become thoroughly mixed, 
grind heavily with the pestle, when rapid detonations will ensue. The 
paper will prevent loose particles from flying into the eyes. The same pre- 
caution should always be observed when pulverizing potassium chlorate. A 
better way is to purchase that salt in powder, or to make a hot saturated 
solution, and pour it out in thin films on panes of glass or old plates. It 
then forms very small crystals, which can be scraped off and dried for use. 
After using, clean out the mortar carefully for other experiments. The 
powder can be wrapped with paper into a hard pellet, and exploded on an 
anvil by a sharp blow from a hammer. Sometimes small bits of phosphorus 
are used instead of sulphur. Great care is then necessary, as the particles 
of burning phosphorus are apt to fly to some distance. 

125. If four measures of a cold saturated solution of potassium bichro- 
mate be mixed with six of concentrated H 2 S0 4 , and the liquid be allowed 
to cool, chromic anhydride crystallizes in crimson needles, which may be 
drained and dried upon a brick. 

The chromic anhydride is a powerful oxidizing agent, as may be shown 
by dropping onto some of the dry crystals a little strong alcohol. The 
alcohol will inflame, while the chromic anhydride turns green. 

132. Sod him— 126. Take a small saucepan, and, having made a little 
pool of water upon a wooden stool, set the saucepan upon it ; then throw in 
a handful of snow or powdered ice, and a handful of common salt ; now 
stir with a stick, and the cold will freeze the saucepan to the stool, even 
before a large fire. 

127. Pill a tall cylinder with a clear saturated solution of NaCl, and pass 
into it at the same time strong currents of NTT 3 and C0 2 gases. A pre- 
cipitate of NaHC0 3 falls. This is known as the Solvay Ammonia soda 



282 DIRECTIONS FOR EXPERIMENTS. 

process. The solution contains NH 4 C1, from which E"H 3 may be recovered 
by treating it with CaO. 

128. Dissolve 150 parts, by weight, of hyposulphite of soda in 15 parts 
boiling water, and gently pour it into a tall test-glass so as to half fill it, 
keeping the solution warm by placing the glass in hot water. Dissolve 100 
parts, by weight, of sodium acetate in 15 parts hot water, and carefully 
pour it in the same glass ; the latter will form an overlying layer on the 
surface of the former, and will not mix with it. When cool, there will be 
two supersaturated solutions. If a crystal of sodium hyposulphite be at- 
tached to a thread, and carefully passed into the glass, it will traverse the 
acetate solution without disturbing it, but, on reaching the hyposulphite 
solution, will cause the latter to crystallize instantaneously in large prisms. 
(Compare note, p. 134.) 

129. Dissolve 40 grs. of common soda in one wine-glass of water, and 
35 grs. of tartaric acid in another. On being poured together in a goblet, 
they will violently effervesce. Use a glass which is large enough to prevent 
any of the liquid from running over. Neatness in experiments is essential 
to perfection, and often to success. At the close of this illustration, evap- 
orate the solution,* and a neutral salt will result. (Compare p. 98). 

I 38. Calcium. — 130. Place a few lumps of marble in the open fire, or in 
an open crucible with a hole at the bottom, and heat it strongly for an 
hour or two. It is converted into quicklime. Place the lumps in an open 
dish, and cover them with water— about one third the weight of the lime. 
The water will be all absorbed by the lime, and slaked lime Ca(OH) 2 pro- 
duced. 

f 39-— 131. Put some of the Ca(OH) 2 in a bottle of water, and cork. The 
water dissolves a very little of the Ca(OH) 2 , and the clear solution forms 
"lime-water." (Compare Ex. 54.) It may be decanted or siphoned off, and 
a fresh supply made by simply filling up the bottle again. This may be re- 
peated as long as solid Ca(OH)^ remains in the bottle. 

132. Pour some of the lime-water into a saucer, and let it stand. It 
becomes covered with a film which may be shown to be a carbonate by 
removing it, placing it in a test-tube, and adding a drop of HC1. Efferves- 
cence will occur, and the gas which comes off will render turbid a drop of 
clear lime-water introduced into the mouth of the test-tube on the end of a 
glass rod. 

I 4 I .—133. Select a medal suitable for the purpose ; paste a shallow rim 
of paper round it, so as to make it like the lid of a pill-box, and anoint the 
surface of the medal very lightly with oil. Mix a little dry plaster of Paris 

* Pour a part of the liquid into an evaporating dish, and place this on the tripod 
over the flame of the spirit-lamp, or upon a hot stove. Heat until a drop of the liquid, 
taken out on the end of a glass-rod and put on a bit of glass, will crystallize as soon as it 
cools. Then set the dish aside to cool, when crystals will soon begin to form.— In this 
connection, it is well to remark that a cook stove will be found of great use in chemical 
experiments, and indeed may, in the laboratory, take the place of the furnace. The oven 
will dry apparatus and chemicals; the heat is sufficient for evaporating solutions, distill- 
ing water, etc., while an excellent sand or water-bath may be readily contrived. 



DIRECTIONS FOR EXPERIMENTS. 283 

with water till it becomes of the consistence of thin cream; apply it 
carefully with a hair-pencil to every part of the surface, so as to exclude 
air-bubbles; then pour a thicker mixture into the mold. Allow it to 
remain for an hour. The cast may then be removed : it will be a reversed 
copy of the medal. 

I 43. See Experiment 80. 

134. Dissolve a little piece of marble in HC1 (see Ex. 51). Clean one end 
of a thin platinum wire by dipping it in HC1, and then holding it in the 
flame of a Bunsen burner repeatedly until it imparts no color to the flame 
when first introduced. Then dip the wire into the CaCl 2 solution, and hold 
it in the flame. An orange-red flame coloration will be obtained, which is 
characteristic of calcium. 

135. Repeat the last experiment with SrCl a and with BaCl 2 . 

1 44. Magnesium.— 136. Burn a piece of magnesium ribbon. It is 
readily kindled by a candle or match. 

I 48.— 137. Repeat Ex. 134 with solutions of K, Na, Li, Cs, Cu. The 
wire must be carefully cleaned before making the experiment with each. 

15 1. Iron.— 138. Pulverize a salt of iron, and heat it with Na 2 CO a on 
charcoal before the blow-pipe. A black powder is obtained, which is at- 
tracted by the magnet. 

139. Mix some iron filings with twice the bulk of flowers of sulphur. 
Heat the mixture in a hard glass tube. The two will unite and form 
ferrous sulphide PeS, which yields H 2 S, when treated with dilute H a S0 4 
(see p. 109). 

157.— 140. Make a strong solution of potassium permanganate, and 
heat to boiling in a test-tube. Pour in a few drops of glycerin; the 
latter is oxidized so violently that a flash may be seen, and part of the 
liquid is ejected from the test-tube. 

161. Copper.— 141. Pill a test-tube nearly full of H 2 0. Pour in it a few 
drops of the solution of copper sulphate. Add NH t OH, and a greenish-blue 
precipitate will be formed, which dissolves when more NH 4 0H is added, 
yielding a dark-blue solution. The copper sulphate may be readily pre- 
pared for this experiment by heating a copper cent with strong sulphuric 
acid. This experiment may be made to show the divisibility of matter by 
weighing the cent, finding what proportion of the whole solution you use, 
and then experiment to see what quantity of water can be taken, and yet 
have the blue color perceptible in the ammonia test. 

142. Besides the ammonia test for copper, the metal may be detected by 
the red metallic deposit formed on an iron nail, dipped into a solution of 
the salt. 

143. Dissolve a piece of Cu in HNO s (see p. 33). Evaporate to a small 
quantity the solution which is obtained, and allow it to cool. If sufficiently 
concentrated, crystals of Cu2N0 3 will be formed. 

144. Repeat Ex. 143 with Cu and strong H 2 SO* (see p. 104). The blue 
crystals are CuSO*. 

1 63. Lead.— 145. If a water contain lead, even in minute quantity, its 
presence is easily ascertained by taking two similar jars of 25 cm. high 



284 DIRECTIONS FOE, EXPERIMENTS. 

of colorless glass, filling both of them with the water, and adding to one of 
the jars 3 or 4 cc. of a solution of sulphuretted hydrogen. A quantity of 
lead less than one part in two millions is easily perceived by the brown 
tinge occasioned, on looking down upon a sheet of white paper ; the jar to 
which the test has not been added serving as a standard of comparison. 

165. Gold.— 146. Place a little gold-leaf in two test-tubes; to one add 
HNO3, to the other PIC1. Even when heated, the gold-leaf will remain un- 
affected in each. Pour the contents of one tube into the other: the Au 
will disappear with effervescence. Evaporate this solution in a small 
porcelain dish till the acid is nearly all driven off: gold chloride will 
be left. 

147. Dilute the solution with 3 or 4 cc. of H 2 0. To a portion of this 
liquid add a solution of ferrous sulphate : a brown precipitate of finely- 
divided reduced Au is obtained, and iron chloride is formed. 

167. Silver.— 148. Dissolve a ten-cent piece in HN0 3 . The solution has 
a bluish color, owing to the presence of the Cu. Dilute with 200 cc. of 
water ; then add a solution of NaCI so long as it forms a precipitate ; white 
flakes of silver chloride are formed. Stir the mixture briskly with a glass 
rod ; the precipitate of AgCl will collect into clots. Pilter the solution. The 
presence of Cu in the clear liquor may be proved by adding to a portion of 
the liquid NH 4 OH in excess : a blue solution is formed. Place the blade 
of a knife in another portion of the filtrate : it will become coated with 
metallic Cu. 

149. Take the precipitated silver chloride, and, after having washed it 
well on a filter, place it in a wine-glass with a little water; add two or 
three drops of H 2 S0 4 , and then place a slip of Zn in contact with the 
chloride, and leave it for twenty-four hours. The chloride will be reduced 
to metallic Ag, which will have a gray porous aspect, while zinc chloride 
will be found in solution. Dif t out the piece of Zn carefully ; wash the Ag 
first with water containing a little H2SO4, then with pure H 2 0. Dry the 
residue. Place a small quantity of it upon an anvil, and strike it a blow 
with a hammer ; a bright metallic surface will be produced. Place a little 
of the gray powder upon charcoal, and heat in the flame of a blow-pipe : 
it will melt into a brilliant malleable bead. Dissolve another portion in 
HNO3 ; red fumes will escape, and silver nitrate be obtained in solution. 

150. Pill a vial half full of a solution of silver nitrate, and add a few 
globules of Hg. The Ag will be precipitated in a few days, forming the 
" silver tree. 11 

151. Place a crystal of AgN0 3 on a piece of charcoal, and heat in the 
reducing blow-pipe flame. A globule of metallic Ag is produced, which is 
soft and malleable. 

152. Ploat a sheet of sized paper on an NaCl solution. When dry, float it 
for three minutes on a solution of AglST0 3 , and dry in the dark. Press a 
fern-leaf on a piece of glass, lay a sheet of this paper on it, and then a thin 
board as large as the glass. Clamp them together with clothes-pins, and 
expose to direct sunlight. When sufficiently black, place in a solution of 
"hypo," and wash thoroughly with water. 



DIRECTIONS FOR EXPERIMENTS. 285 



ORGANIC CHEMISTRY. 

| 95.— 153. Dissolve about 20 grams of grape-sugar in a liter of water, 
and put the solution, with a little yeast, in a flask connected with a cylin- 
der or bottle, as shown in Eig. 52, A and B. The cylinder B contains some 
clear lime-water, and the end of the short, bent tube is plugged with cotton 
to prevent the air from entering freely. After standing some hours in a 
warm room, B will contain a white precipitate of CaC0 3 , formed by the C0 2 
produced by the fermentation. The contents of A will have an alcoholic 
odor, and, by distilling, a dilute alcohol could be obtained. 

200.— 154. Pour a little alcohol into a small beaker, and suspend over it 
a coil of Pt wire, which has been heated until it glows. It will continue to 
glow, owing to a slow oxidation of the alcohol vapors. The peculiar pene- 
trating odor observed is due to aldehyde. 

155. Another instructive experiment by which aldehyde is produced is as 
follows : Add to a solution of potassium bichromate, sulphuric acid and a 
little alcohol. On heating, the odor of aldehyde will be perceived, while the 
red solution becomes green. Explain. 

156. Eormic acid may be made by distilling a mixture of one part of oxalic 
acid and ten parts of glycerin. The dilute acid thus obtained may be used 
for making copper formate : Dissolve in the acid freshly precipitated and 
washed copper oxide until no more is taken up ; filter and concentrate the 
solution, if necessary, by evaporation, when copper formate will separate in 
beautiful crystals. 

203.— 157. Make oxalic acid by pouring ordinary strong nitric acid upon 
sugar (6 pts. of acid to 1 of sugar), and heating gently till the reaction 
begins. The sugar is oxidized with some violence and evolution of 
abundant red fumes. On cooling, oxalic acid will crystallize out. More 
can be obtained by evaporation. Purify the acid by recrystallizing it from 
water. 

205.— 158. Ether may be made by heating to 140° C. a mixture of 100 
grams of alcohol and 180 grams concentrated sulphuric acid. The operation 
should be conducted in a retort connected with a cooler. 

206.— 159. Mix in a test-tube equal parts of acetic acid and alcohol, 
and add a little concentrated H 2 S0 4 . The odor is that of ethyl acetate, or 
acetic ether. 

2 I O.— 100. Add to a solution of sodium carbonate a little alcohol, and 
then, after warming it to about 80° C, introduce gradually a few crystals of 
iodine. Yellow crystals of iodoform will separate from the solution. 

2 I 9.— 161. To one gill of water, add 15 or 20 grains of strong H 2 S0 4 . 
Place in a large flask, and heat. "While boiling, drop in slowly two drams 
of starch, finely powdered. Boil for several hours, adding water as may be 
necessary. Finally, drop in slowly fine chalk until the liquid is neutral; 
then cool, filter off the calcium sulphate. The solution contains grape- 
sugar. Test it as described in the next two experiments. 



286 DIRECTIONS FOR EXPERIMENTS. 

162. Put a little AgNO s solution in a test-tube, and add aqua ammonia 
slowly until the brown precipitate has again dissolved. Pour some of this 
into a second test-tube, and add a solution of grape-sugar. On boiling, 
the silver will be reduced in the form of a brilliant mirror on the side of 
the tube. . 

163. Take a solution of CuS0 4 , and add enough tartaric acid to prevent 
its being precipitated by KOH. Then add enough KOH solution to make 
it strongly alkaline. Boil this solution, and add, drop by drop, a dilute 
solution of grape-sugar. The intensely blue color disappears, and a red pre- 
cipitate of Cu a O is produced. This is called Fehling^s test, and is employed 
to detect sugar in diabetic urine. By taking proper precautions, the amount 
of the sugar may be accurately determined. 

222.— 164. Mix together in a test-tube 2 parts of H a S0 4 and 1 part of 
HN0 3 , and, when cold, allow some benzene to flow into it, a few drops at 
a time, waiting each time till the reaction is complete, and keeping the 
mixture cool. On pouring the mixture into water, it will be found that the 
benzene no longer floats on water as before, and has acquired a very 
agreeable odor. An atom of H has been replaced by N0 3 , forming nitro- 
benzene, C 6 H 5 N0 2 . The vapor of the nitro-benzene should not be inhaled. 

165. Dissolve a little aniline in water, and add a filtered solution of 
bleaching powder. A purple color is produced. 

237.— 166. Make a dilute solution of gelatin, and add a solution of tan- 
nic acid ; a leathery precipitate is formed. 

240.— 167. Pill a test-tube one third full of fresh milk, and add an equal 
volume of water, then a little acetic acid (or rennet), and allow it to stand 
a short time; filter out the precipitate, and wash with water. The pre- 
cipitate consists of casein and fats. The filtrate contains sugar, as may be 
shown by its reducing action on an alkaline solution of tartrate of copper. 
Remove the precipitate from the filter, and shake it up in a test-tube with 
ether. This dissolves out the fat. Pilter again ; let the filtrate evaporate, 
and the fat will be left in a pure state. 

168. Evaporate a larger portion of milk to dryness, and heat until the 
residue is quite white. Dissolve in water, filter, and test for chlorides with 
AgNO s . 

243.— 169. Mix intimately 10 grains of gelatin with 50 grains of soda- 
lime, and heat strongly ; NH 3 gas will be evolved, and can be detected by 
its odor, its action on reddened litmus-paper, and by fuming with HC1. 

250.— 170. The ordinary photographic process, as given on p. 171, is a 
good illustration of the power of the sun's rays. 

171. Dissolve 1 gram of ammonia-citrate of iron in 20 cc. of water ; add 
to it 20 cc. of a solution of K 4 FeCy 6 , made in the same manner. Keep the 
mixed solution in the dark. Float a sheet of white paper on the solution, 
and allow it to dry. Cover a plate of glass with black varnish, and before 
it dries write upon it with any sharp-pointed instrument. When perfectly 
dry, place it over a sheet of the prepared paper, and expose two or three 
hours to bright sunlight. Remove, and wash well in cold water. You will 
have the writing in blue on a white ground. 



DIRECTIONS FOR EXPERIMENTS. 287 

172. Mix together equal volumes of a solution of gelatin and a solution 
of K 2 Cr. 2 7 , and add a little tincture of logwood. Pour it into a flat dish, 
and float upon it a sheet of unruled writing-paper, and dry in the dark. 
Expose under a negative (p. 172), or fern leaves, to direct sunlight for an 
hour, then wash thoroughly with warm water. Bichromated gelatin is 
rendered insoluble by exposure to sunlight. This principle is employed in 
all photo-engraving processes. 

173. Mix together equal volumes of H and CI in the dark, fill a small 
glass bulb, and throw it up into a bright beam of the sun, when it explodes 
ivith violence. Do not at any time hold the bulb in the hand, or place it within 
several feet of the eyes. 

174. Plants decompose CO a in the sunlight. (See p. 89 and Exp. 70.) 



QUALITATIVE ANALYSIS, 

FOR BEGINNERS. 



[The following pages on analysis were prepared by Prof. E. J. Hallock, 
Ph.D., of Boston.] 

In order to be able to analyze almost every inorganic sub- 
stance met with in the arts, or sold in the shops, it is only 
necessary for the student to familiarize himself with the reac- 
tions of about twenty-six metals and a dozen acids. To be able 
to apply these tests with certainty, in all cases, and to know 
the easiest and best methods of dissolving the substance, consti- 
tute a qualitative chemist. 

For reasons which will appear farther on, metals are divided 
into five groups. 

The First Group embraces lead, silver, and the mercurous 
salts of mercury. They are classed together because they are the 
only metals which are precipitated from solution by hydrochloric 
acid. The student should take a solution of lead nitrate, Pb 
2N0 3 , formed by dissolving litharge or lead in nitric acid, or 
some lead acetate solution (see page 164), and try the following 
tests, making a note of his results. With HC1 a white precipi- 
tate of PbCl 2 is formed. This precipitate is filtered out and 
washed. It dissolves in boiling water, and crystallizes from 
this solution on cooling. To another portion of the solution add 
H 2 S0 4 ; a white precipitate of PbS0 4 is produced, which is insol- 
uble in H 2 0. To a third portion add potassium chromate, 
K 2 Cr0 4 ; a yellow precipitate is formed. To another portion add 
KI ; a yellow precipitate is again produced, but it dissolves in 
boiling water, and forms beautiful crystals on cooling. 

Repeat each of these tests with silver nitrate, AgN0 3 {experi- 
ment 149). The precipitate with HC1 is insoluble in boiling H 2 0, 
but dissolves in NH 4 OH, and is reprecipitated by HN0 3 . With KI 
a yellowish-white precipitate is formed. 



QUALITATIVE ANALYSIS 289 

Repeat with mercurous nitrate, HgN0 3 , made by the action 
of dilute HN0 3 on an excess of Hg, in the cold. We have with 
HC1 a precipitate of calomel (HgCl), (page 176), which is insoluble 
in H 2 0, and blackens on adding NH 4 OH, but does not dissolve. 
KI forms a greenish-yellow precipitate. 

Separating Metals of Group I.— Mix the solutions of the 
three metals, and add HC1. Miter, and boil the precipitate in 
water; filter hot, and to the filtrate add K 2 CrQ 4 . The yellow 
precipitate proves that lead is present. Boil the residue in 
ammonia and filter; to the nitrate add HN0 3 . A white precipi- 
tate proves silver present. The black insoluble residue is a 
compound of mercury (Hg 2 H 2 NCl). 

The Second Group embraces the mercuric salts of mercury, 
together with Pb, Bi, Cu, Cd, As, Sb, Sn, Au, and Pt. They are pre- 
cipitated from acid solutions as sulphides by passing H 2 S gas 
through the solution. (See experiment 103.) Of these HgS, PbS, 
Bi 2 S 3 , CuS, and CdS are insoluble in ammonium sulphide, 
(NH 4 ) 2 S, and constitute the first division of this group. The 
sulphides of the remaining five metals are soluble in (NH 4 ) 2 S, * 
and form the second division. 

Pass H 2 S gas into a solution of corrosive sublimate (HgCl 2 ) 
(page 176) ; a precipitate is formed which is at first white, then 
yellow, red, and finally black. It is insoluble in (NH 4 ) 2 S, and in 
HN0 3 . It dissolves in aqua regia and gives a gray precipitate 
with an excess of SnCL. Repeat the first experiment with some 
lead solution ; a black precipitate is formed, soluble in boiling 
HNO3. In this solution a white precipitate of PbS0 4 is formed 
on adding hLSO^. Add a few drops of KI solution to the origi- 
nal solutions of HgCl 2 , and Pb2NCL ; in the former case the pre- 
cipitate (Hgl 2 ) is red, in the latter (Pbl 2 ) it is yellow. These 
tests are characteristic of the metals when alone. Pass H S 



* (NHJ 2 S is prepared, according to Presenilis, by saturating a given 
volume of ammonia solution (specific gravity 0.96) with. H 2 S gas, and add- 
ing to it an equal volume of the ammonia. The solution, which is at first 
colorless, soon becomes yellow by keeping, or may be at once converted 
into the yellow sulphide by the addition of sulphur. It should yield no 
precipitate with magnesium sulphate (Epsom salt). This re-agent is decom- 
posed by acids, sulphur being precipitated. 



290 QUALITATIVE ANALYSIS. 

into Bi3N0 3 solution;* a black precipitate is formed; dissolve 
in HN0 3 ; add a drop of H 2 S0 4 to prove it is not lead; then 
cautiously add ammonia, which produces a white precipitate of 
Bi(OH) 3 . Repeat all the above experiments with CdS0 4 solution; 
the precipitate with H 2 S is a beautiful yellow, soluble in HN0 3 , 
but insoluble in KCy. Pass H 2 S in CuS0 4 solution, and a 
brownish-black precipitate will be formed, soluble in HN0 3 and 
in KCy. Salts of copper have a bluish color, which becomes 
more intense on adding NH 4 HO. {Experiment 141.) With 
potassium ferrocyanide (K 4 FeCy 6 ) they give a reddish-brown pre- 
cipitate insoluble in HC1. 

Separating Metals of Second Group, First Division.— After 
the student has made all the above reactions he may mix the 
solutions of the five metals and proceed to separate them. Some 
of the lead is precipitated by HC1, and is filtered out before H 2 S 
is passed through the solution. The precipitate with H 2 S is 
boiled in HN0 3 , and HgS remains as a residue. When the origi- 
nal solution was very acid, S will be found mixed with HgS in 
the residue insoluble in HN0 3 . To the filtrate add a little H 2 S0 4 to 
precipitate the lead present; filter from the PbS0 4 and add 
NH 4 OH ; Bi(OH) 3 is precipitated. The precipitate, dissolved in 
aqua regia and concentrated by evaporation, should give a white 
precipitate if poured into water. The addition of NH 4 C1 aids 
this reaction. The blue filtrate from the BI precipitate is boiled 
with KCy, care being taken not to inhale the fumes, and H 2 S 
added ; CdS forms a yellow precipitate. The presence of Cu in 
the filtrate from CdS is proved by the formation of a reddish- 
brown precipitate with K 4 FeCy 6 , after HN0 3 has been added to 
the solution. 

The most interesting metal of group second, second division, 
is As. H 2 S in an HC1 solution of As 2 3 gives a yellow precipitate 
As 2 S 3 ; it is soluble in (NH 4 ) 2 S, and in (NH 4 ) 2 C0 3 . The neutral 
salts of arsenious acid yield with AgN0 3 , a yellow precipitate, 

* When Bi solutions are diluted with water, basic salts are precipitated 
unless there be much free acid present. This reaction is most sensitive 
with BiCl 3 , so that HC1 may be used to dissolve the Bi3N0 3 for the H 2 
test. 



QUALITATIVE ANALYSIS. 291 

Ag 3 As0 3 , soluble in HN0 3 . A small piece of bright green paper 
often contains enough of this metal to give several characteristic 
tests. Apply a single drop of nitric acid to the paper ; a moment 
after neutralize with ammonia and observe the color, a deep 
blue always indicating copper. When the white fumes have 
nearly disappeared, apply to the same spot a drop of AgN0 3 ; a 
yellow ring indicates As. The most delicate test for As as well as 
Sb is Marsh's test (see page 119). The mirror formed by As on 
porcelain is soluble in sodium hypochlorite (Labarraque's solution); 
that of Sb is insoluble in this. If AsH 3 is passed into AgN0 3 , 
metallic Ag is precipitated and enough HN0 3 is set free to keep 
the As in solution until it is carefully neutralized with NH 4 OH, 
when a precipitate of Ag 3 As0 3 appears. 

Antimony closely resembles As in its reactions. Pass H 2 S 
into a solution of tartar emetic {experiment 103), and an orange- 
colored precipitate, Sb 2 S 3 , will be formed, soluble in (NH 4 ) 2 S, 
and re-precipitated on adding dilute HC1 to this solution. This 
precipitate is soluble in strong HC1, while the corresponding 
arsenic precipitate is not. Put some of the Sb solution in a new 
Marsh's apparatus. The mirror is insoluble in sodium hypo- 
chlorite. 

Tin dissolves in HC1, but is oxidized to a white powder by 
HN0 3 without dissolving. There are two series of tin salts ; SnCl 2 
gives a dark brown precipitate with H 2 S ; SnCl 4 a yellow pre- 
cipitate with H 2 S, both soluble in yellow (NH 4 ) 2 S. SnCl 2 forms 
with an excess of HgCl 2 , a white precipitate of HgCl ; but when 
SnCl 2 is in excess a gray precipitate of Hg is formed. On adding 
dilute HC1 to the (NH 4 ) 2 S solution of the sulphide, it is re-pre- 
cipitated yellow, even though it may have been brown before it 
was dissolved. It dissolves in strong HC1. 

G-old and platinum are distinguished from all other metals by 
their insolubility in HC1 or HN0 3 , but are converted into soluble 
chlorides by aqua regia. The characteristic test for Au salts is 
SnCl 2 mixed with SnCl 4 , the purple of Cassius being formed. 
PtCl 4 will give a yellow precipitate with NH 4 C1 and alcohol, 
(NH 4 ) 2 PtCl 6 . 

Separating Metals of Second Group, Second Division. — Into 
an acid solution of Sn, Sb, and As, pass H 2 S gas. Filter and 



292 QUALITATIVE ANALYSIS. 

dissolve precipitate in (NH 4 ) 2 S to remove any members of first 
division, if these are to be looked for. Re-precipitate the sul- 
phides with dilute HC1, filter and wash. Then treat with strong 
hot HC1 ; if a residue remains it is probably As 2 S 3 . Dissolve 
this in HC1 with the aid of a little solid KC10 3 , and test, as de- 
scribed in experiment 110, or in Marsh's apparatus. The filtrate 
from As 2 S 3 contains Sb and Sn. Put this in another Marsh's 
apparatus ; the mirror will be insoluble in hypochlorites. When 
the zinc has all dissolved, take the residue and dissolve it in 
HC1 and test for Sn with HgCl 2 . 

As Au and Pt are seldom to be sought for, this part of the 
separation may be omitted. The mixed sulphides of Au, Pt, As, 
Sb, and Sn may all be placed in Marsh's apparatus, as directed 
in the table on page 302, when the As and Sb combine with H, 
and are separated by passing the AsH 3 and SbH 3 into AgN0 3 . 
The metallic Sn, Au, and Pt remain in the H generator ; the Sn 
is then dissolved out with HC1, and tested with HgCl 2 ; the Au 
and Pt are dissolved in aqua regia and tested in separate portions 
of the solution, as described above. 

Group Third embraces Co, Ni, Fe, Cr, Mn, Al, and Zn. They 
are precipitated by (NH 4 ) 2 S from neutral or alkaline solutions. 
The characteristic test for Co, is the blue color imparted to a 
borax bead. N i alone gives, in the outer blow-pipe flame, a reddish- 
brown bead, in the inner gray. Both give with (NH 4 ) 2 S black 
precipitates insoluble in dilute HC1. If KN0 2 and acetic acid are 
added to a solution of Co and Ni, the former is slowly precipitated 
and not the latter. To a solution of FeS0 4 , add a drop of potas- 
sium ferricyanide (K 3 FeCy 6 ); a blue precipitate is formed. To 
another portion add (NH 4 ) 2 S ; a black precipitate is formed, soluble 
in dilute HC1, from which solution it is re-precipitated by NaOH, 
as greenish Fe(OH) 2 . Eepeat the latter test with ferric chloride 
(Fe 2 Cl 6 ) and reddish brown Fe 2 (OH) 6 is precipitated. Fe 2 Cl 6 gives 
with K 4 FeCy 6 a precipitate of Prussian blue. In a glass of water 
place one drop of Fe 2 Cl 6 , and add a few drops of potassium 
sulphocyanide (KCyS) ; the liquid acquires a blood-red color. Iron 
salts also give characteristic colors to the borax beads ; yellow 
in the outer and green in the inner flame. To a solution of MnS0 4 , 
add (NH 4 ) 2 S ; a flesh-colored precipitate is formed, soluble in HC1 ; 



QUALITATIVE ANALYSIS. 293 

NaOH precipitates Mn(OH) 2 . The borax bead with Mn acquires 
an amethyst-red color (see note, page 122) in the outer blow-pipe 
flame. Fused with Na 8 C0 9 and KN0 3 a green mass is formed. 
(NH 4 ) 2 S gives with the salts of Cr, a greenish precipitate of 
Cr 2 (OH) 6 , soluble in HC1, and re-precipitated when boiled with NaOH. 
Fused with Na 2 C0 3 and KN0 3 it forms yellow potassium chromate 
K 2 Cr0 4 . When this is dissolved in water and acidified with acetic 
acid, it yields a yellow precipitate with Pb2N0 3 . To a solution 
of alum add (NH 4 ) 2 S; it forms a white precipitate soluble in 
dilute HC1. To the second portion add NH 4 OH, a white precipitate; 
and to a third add NaOH and boil; the white precipitate at first 
formed dissolves again. To a solution of ZnS0 4 , obtained in 
experiment 30, add NH 4 0H slowly. The white precipitate at 
first formed dissolves when more NH 4 OH is added. In this solu- 
tion H 2 S causes a white precipitate of ZnS. 

Separation of Metals of Group Third. — Some NH 4 C1 and 
NH 4 OH is first added ; then (NH 4 ) 2 S. The precipitate is digested 
in dilute HC1; Ni and Co are sought in the residue. The filtrate 
is boiled with NaOH for half an hour in a porcelain dish, and 
filtered. To the filtrate HC1 is added until acid, then NH 4 OH, 
which precipitates Al ; Zn is precipitated from the filtrate from 
this by H 2 S or (NH 4 ) 2 S. The residue, containing Fe, Mn, and Cr, is 
fused with pure KN0 3 and Na 2 C0 3 ; if the mass is green, Mn is 
indicated ; if yellow, Cr. One half of the mass is warmed with 
water ; the insoluble residue is tested for iron ; the filtrate is 
tested for Cr by first neutralizing with acetic acid, and then add- 
ing Pb2N0 3 . The test for Mn is to boil some of the fused mass 
in HN0 3 , with red lead; a beautiful rose pink is produced from 
the formation of KMn0 4 . 

Group Fourth embraces the metals of the alkaline earths, 
Ba, Sr, and Ca, whose carbonates, precipitated by (NH 4 ) 2 C0 3 , are 
insoluble in H 2 0, but soluble in acetic acid or in HC1. BaCl 2 
forms with H 2 S0 4 or a clear solution of CaS0 4 , a precipitate in- 
soluble in acids; K 2 Cr0 4 precipitates yellow BaCr0 4 . Ba com- 
pounds impart a green color to the flame of an alcohol lamp or 
Bunsen burner. CaCl 2 , with ammonium oxalate, yields a white 
precipitate insoluble in acetic acid. H 2 S0 4 produces a white 
precipitate of CaS0 4 , slightly soluble in water and acids. Ca 



294 QUALITATIVE ANALYSIS. 

salts color the flame yellowish red. SrCl 2 gives a white precipi- 
tate with a clear solution of CaS0 4 ; if the solution is dilute, 
half an hour is required for the precipitation. Sr colors the 
flame crimson-red. 

Separating Metals of G-roup Fourth. — Some NH 4 C1 is first 
added, if not already present in the solution, then (NH 4 ) 2 C0 3 . 
The precipitate is dissolved in acetic acid, and divided in two 
portions. To one is added K 2 Cr0 4 ; Ba is precipitated yellow, 
and the filtrate is tested for Sr by means of CaS0 4 . H 2 S0 4 is 
added to the other portion, the precipitate filtered out. NH 4 OH 
is added to the filtrate, which is now tested for Ca with am- 
monium oxalate. 

Group Fifth embraces Mg, K, Na, and Li. As lithia is very 
rare, we omit its reactions. MgS0 4 yields a white precipitate of 
Mg(OH) 3 on the addition of NH 4 OH, unless the solution contains 
NH 4 C1; hence the necessity of adding NH 4 C1, before testing for 
groups III. and IV., where NH 4 OH would otherwise throw down 
Mg. The salts of Mg give a white precipitate with sodium 
phosphate, Na 2 HP0 4 , and NH 4 OH. KC1 yields a yellow precipi- 
tate with PtCl 4 ; Potassium tartrate is precipitated from con- 
centrated solutions by sodium tartrate. K 2 S0 4 gives a white 
precipitate with 2HF,SiF 4 and alcohol. K imparts a violet color 
to flame, which appears reddish violet when viewed through 
blue glass. Na is not precipitated by any of the above re- 
agents; it imparts an intense yellow color to flame. K, Na, and 
Li, as well as Ca, Ba, and Sr, are easily detected by the spectro- 
scope. 

Ammonia is liberated from its compounds by heating with 
NaOH or Ca(OH) 2 , and is then recognized by the smell, by bluing 
red litmus, and by producing white fumes when a rod moistened 
with HC1 gas is held over it. (See page 35.) 



TESTS FOR ACIDS. 

The acids do not admit of the strict grouping and successive 
separation employed for metals, and we will rest content with 
mentioning the simplest tests for the principal acids, beginning 
with those of the halogens : 



QUALITATIVE ANALYSIS. 295 

HC1 with AgN0 3 , white precipitate, soluble in NH 4 OH, not in 
HN0 3 . 

HI with AgN0 3 , yellowish precipitate, almost insoluble in 
NH 4 OH. 

HI with HgCl 2 , red precipitate, soluble in KI. 

HI with starch paste and CI solution or bleaching powder, 
blue color. (See page 101.) 

CaF 2 with H 2 S0 4 liberates HF, which attacks glass. (See page 
102.) 

HBr with starch paste and CI water, an orange-yellow color. 

H 2 S0 4 with BaCl 2 , white precipitate, insoluble in HC1. 

Si0 2 is insoluble in H 2 0, as are most of the silicates except 
those of K and Na. In analyzing the soluble silicates, they are 
first evaporated to dryness with excess of HC1, the soluble chlo- 
rides dissolved in H 2 or HC1, and the Si0 2 left as a gritty pow- 
der. 

Boric Acid is detected by placing it in a dish containing alco- 
hol and H 2 S0 4 , and igniting the alcohol. A green tinge to the 
flame indicates B. If a mixture of glycerin and borax is brought 
into a flame and removed as soon as it takes fire, the green 
flame is easily recognized. (Experiments 112 and 113.) 

H 3 P0 4 with neutral AgN0 3 , yellow precipitate, soluble in HN0 3 
and NH 4 0H. 

H 3 P0 4 with solution of ammonium molybdate in HN0 3 , a fine 
yellow precipitate. 

H 3 P0 4 with MgS0 4 solution containing NH 4 C1 and NH 4 OH, a 
white precipitate soluble in acids. (See test for Mg, page 29-1.) 

C0 2 . Carbonates effervesce on the addition of acids, C0 2 being 
set free, which extinguishes a match inserted in the test-tube. 
The ear is often able to detect slight effervescence not otherwise 
perceptible. 

HN0 3 is not precipitated by any re-agent. Into a test-tube 
containing some nitrate, drop a crystal of FeS0 4 , then allow a 
few drops of H 2 S0 4 to flow down the side of the test-tube which 
is held inclined. A characteristic dark-brown ring forms imme- 
diately. If Cu and strong H 2 S0 4 are heated with a nitrate, red 
fumes are given off. A nitrate heated on charcoal deflagrates. 

Chlorates deflagrate more violently than nitrates. H 2 S0 4 lib- 
erates C1 2 4 , which is betrayed by its color and odor. If a crys- 



296 QUALITATIVE ANALYSIS. 

tal of KC10 3 and a piece of P be placed in a glass of water, and 
a drop of H 2 S0 4 conveyed to it by a pipette or tube, the P takes 
fire and burns under water (page 131). All experiments with 
chlorates must be performed with minute quantities, because of 
the great danger of explosions. 

SO 2 is easily recognized by its odor. When sulphites are 
treated with HC1, the S0 2 is evolved. 

If CI gas be given off on heating a substance in HC1, the 
presence of a binoxide may be suspected. (See page 92.) 

If an odor of H 2 S is perceived on treating a substance with 
HCl, it is evidently a sulphide. Heated with strong HN0 3 , sul- 
phides are converted into sulphates. 

HCy with AgN0 3 , white precipitate soluble in KCy ; difficultly 
soluble in NH 4 OH. Care must be taken in handling the poison- 
ous cyanide. On adding HCl to a cyanide, HCy is liberated, and 
is detected by the odor, which resembles bitter almonds. 

H 4 FeCy 6 with AgN0 3 , white precipitate insoluble in NH 4 OH, and 
in HN0 3 . With Fe 2 Cl 6 , Prussian blue [Fe 4 (FeCy 6 ) 3 ] is formed. 

Oxalic Acid, H 2 C 2 4 , yields a white precipitate with CaCl 2 , 
which is insoluble in acetic acid. 

When several acids are present they are tested for in separate 
portions. As 2 3 may occasionally be mistaken for H 3 P0 4 . BaCl 2 
will yield precipitates with carbonic, oxalic, phosphoric, and sul- 
phuric acids, but they all dissolve in HCl except BaS0 4 . 

To test for HCl in the presence of HI, or HBr, or both, the dry 
powder is mixed with dry K 2 Cr 2 7 , and pure concentrated H 2 S0 4 
added, and heated, when Cr0 2 Cl 2 is given off as a brownish-red 
gas; and a glass rod dipped in NH 4 OH and held over the tube 
becomes slightly yellow if CI is present, from the formation of 
(NH 4 ) 2 Cr0 4 . If the substance to be tested contains only Br and I, 
these two may be separated by CuS0 4 and H 2 S0 3 , which precipi- 
tates the latter as Cu 2 I 2 and permits the use of the starch test 
for Br. Or chloroform is added to the solution and a very little 
CI water, or solution of bleaching powder, is then poured in and 
the test-tube well shaken. Then I is liberated and dissolved by 
the chloroform, imparting to it the well-known purple color, the 
intensity of which conceals the yellowish-brown color of the Br 
likewise set free and dissolved. On adding more CI water, the 
violet disappears, leaving only the yellow color due to the Br. 



QUALITATIVE ANALYSIS. 297 

PRELIMINARY TESTS. 

A few tests in a dry way will give some clew to the sub- 
stances present ; but in a complete analysis every acid and every 
metal must be sought for. 

I. Heating in a Tube of Hard Glass closed at one end. — 
If the substance blackens, organic matter is probably present. 
If vapors escape, they are tested for C0 2 , S0 2 , H 2 S, etc. If a 
sublimate is formed, it may be S, I, Hg, a compound of Hg, As, 
Sb, or a salt of ammonium. 

II. Heating on Charcoal. — A small portion of the substance 
is placed on charcoal and exposed to the inner blow-pipe flame. 
(See page 83.) If an infusible white residue remains, moisten it 
with Co2N0 3 and heat it again; a fine blue indicates Al, a phos- 
phate or Si0 2 , a reddish tint Mg, a green color Zn. Mix another 
portion with Na 2 C0 3 and heat on charcoal in the reducing name. 
If a metallic globule is formed without an incrustation, it indi- 
cates Au, Cu, or Ag, as the color is yellow, red, or white. A very 
fusible and malleable globule surrounded by a yellow incrusta- 
tion indicates Pb ; if the incrustation is white it may be Sb or Sn ; 
if orange, yellow while hot, becoming lighter on cooling, Bi. The 
globules of Sb and Bi are hard and brittle. If As is present, an 
odor resembling garlic is noticed. The charcoal tests will be of 
little use to the student, except for detecting Ag and Pb, until prac- 
tice has given him considerable facility in the use of the blow-pipe. 

III. Borax Beads. — Several metals impart characteristic 
colors to borax glass when fused with it before the blow-pipe. 
The end of a piece of platinum wire is bent to form an eye as 
large as this letter O ; it is next dipped in borax and held in the 
flame until fused, then dipped in the powdered substance and 
fused again. The color varies according as the oxidizing or 
reducing flame is employed. 

Color. Oxidizing. Reducing. 

Blue Co and Cu Co 

Green Cr and Cu Fe and Cr 

Red Fe and Ni Cu (opaque) 

Amethyst - . . , M n 

Yellow to brown Fe 

Colorless SI, etc. Mn 

Gray Ni 



298 QUALITATIVE ANALYSIS. 



SOLUTION. 

The first thing to be done before beginning an analysis is to 
bring the substance into solution. Distilled water is first em- 
ployed ; if a residue insoluble in water remains, it is treated with 
acid. In analyzing metals and alloys, nitric acid is the usual 
solvent; aqua regia being required only for the noble metals. 
If Sn is present, and Pb and Ag absent, HCl is employed. Min- 
eral substances, if insoluble in any acid, are rendered soluble by 
fluxing, or fusing with pure Na 2 C0 3 and K 2 C0 3 . As a very high 
heat is required for fluxing, deflagration is sometimes preferred. 
One part of the insoluble powder, is intimately mixed with two 
parts of dry sodium carbonate, two parts pulverized charcoal, 
and twelve parts niter. The mixture is placed in the open air 
and a match applied. A portion of the porous mass produced 
will be soluble in water, the remainder in acids. The two solu- 
tions are to be preserved and tested separately. The metals will 
be found in the acid solution, while the acids will be found in 
the aqueous solution. Before beginning the regular course of 
analysis with these solutions, part of the aqueous solution is 
evaporated to dryness with excess of HCl to render all the Si0 2 
insoluble. In separate portions of the aqueous solution, the 
various acids are sought as above described (p. 294). 

If a portion of the substance is insoluble in H CI after fluxing, 
it is probably silicic acid, or an undecomposed silicate, and may 
be rendered soluble by fluxing a second time. 

A platinum crucible must never be employed if reducible 
metals, especially Pb, As or Sb have been found in the prelim- 
inary tests. 



EXAMPLES FOR PRACTICE. 



After the student has made all the tests above given, and 
succeeded in separating the members of each group from each 
other, especial care being given to the separation of lead from 
bismuth, copper from cadmium, arsenic from antimony, and 
nickel from cobalt, the teacher may give out the following or 
similar substances for analysis, not following the precise order 
of the book, so that the student shall not know what substance 



, 



QUALITATIVE ANALYSIS. 



299 



he is analyzing. Each student should record the results of every 
analysis in a note-book which he will rule for each analysis as 
shown under No. 1. 

1. Analysis of CuS0 4 . — A crystal of this salt as large as a 
pea is given to a student, who dissolves it in distilled water in 
a test-tube and divides the solution in two portions. To one is 
added a drop of HC1, which should produce no precipitate. H 2 S 
is then added until all the Cu is precipitated. The solution is 
then filtered and the precipitate thoroughly washed on the filter. 
H 2 S should produce no precipitate in the filtrate. The precipitate, 
which is found to be insoluble in (NH 4 ) 2 S, is dissolved in HN0 3 , 
and no residue, except perhaps a little sulphur, remains, so that 
the absence of Hg- is established. H 2 S0 4 produces no precipitate 
in this solution, hence Pb is absent. Ammonia, added in excess, 
gives no precipitate (Bi is absent), but the intense blue color char- 
acteristic of Cu, and as only one metal is to be sought, the pres- 
ence of Cu is further proved by adding HN0 3 and K 4 FeCy 6 , which 
causes a reddish-brown precipitate. The second portion of the 
solution is used in testing for acids. To a small quantity of this 
some BaCl 2 is added, and if the precipitate is insoluble in HC1, 
the acid present must be H 2 S0 4 . The results are recorded in 
tabular form thus : 



ANALYSIS NO. 1. 
Substance Blue, Soluble in H.,0. 



GROUP I. 


GROUP II. 


GROUP III. 


GROUP IV. 


GROUP V. 




HC1 


H 2 S 


(NHJ 2 S 


(NH 4 ) 2 C0 3 

• 









Brown pre- 
cip., sol. in 
HN0 3 . 

NH 4 0H blue. 

K 4 FeCy 6 

brown. 

Cu. 








G 





Acids: BaCl 2 ; ^VTiite precipitate insol. in HC1 , 



H.,S0 4 



300 QUALITATIVE ANALYSIS. 

2. Analysis of HgCl 2 . — This salt is likewise very soluble in 
H 2 0. To one portion of the solution add HC1, and H 2 S. The lat- 
ter produces a black precipitate, insoluble in HN0 3 , which indi- 
cates Hg, but a confirmatory test must be employed, which is 
to dissolve the precipitate in aqua regia and add SnCl 2 . To a 
second portion add some BaCl 2 , which will cause no precipitate. 
To a third portion add AgN0 3 , which produces a white precipi- 
tate, insoluble in HN0 3 , but soluble in NH 4 OH, proving the pres- 
ence of HC1. 

3. Analysis of FeS0 4 . — Acidify a portion of the solution with 
HC1, add a little H 2 S to prove that no metals of the second group 
are present, and then (NH 4 ) 2 S, which produces a black precipi- 
tate, which is treated as directed for Group III., page 293. To 
some of the original solution a drop of K 3 FeCy 6 is added, when 
the blue color proves the presence of Fe. 

4. Analysis of Sr2N0 3 . — Dissolve in water, test for Groups 
I., II., and III., which may occur as impurities, and then add 
(NH 4 ) 2 C0 3 . The white precipitate is filtered out and washed, then 
dissolved in acetic acid. To one portion add K 2 Cr0 4 , when the 
absence of Ba is shown, and the Sr test may next be made, by 
adding NH 4 OH and CaS0 4 . The precipitate forms slowly. In 
the original solution no precipitate is formed by BaCl 2 or AgN0 3 , 
and a careful test for HN0 3 is made with FeS0 4 and H 2 S0 4 , as 
described on page 295. 

5. Analysis of BaS0 4 . — This substance refuses to dissolve 
either in H 2 or in acids. It is boiled repeatedly with fresh 
quantities of Na 2 C0 3 and filtered boiling hot ; or fluxed with KN0 3 
and Na 2 C0 3 . The filtrate contains Na 3 S0 4 ; the residue is BaC0 3 
(and unaltered BaS0 4 ). The residue is dissolved in HC1 and tested 
for Ba with K 2 Cr0 4 or SrS0 4 solution. 

6. Analysis of a Coin. — A silver coin is dissolved in HN0 3 , 
then diluted and the Ag precipitated with H CI as AgCl. From this 
metallic silver is precipitated on a piece of clean zinc placed in the 
precipitate, which is moistened with dilute H 2 S0 4 . In the blue 
filtrate will be found all the copper, which may be tested for as 
above. If, instead of a silver coin, a nickel coin is used, HC1 will 
give no precipitate, the Cu will be thrown down by H 2 S, and the 
Ni by (NH 4 ) 2 S. In analyzing compound substances, great care 
must be taken that all the metals of a certain group are precipi- 



QUALITATIVE ANALYSIS. 301 

tated before proceeding to the next, and for this purpose, after 
precipitating the Ag with HC1, a drop of HC1 is added to the filtrate 
to ascertain whether any Ag remains in solution. Precipitates 
should also be well washed, but the wash-water is not added 
to the filtrate. 

7. Analysis of Mixed Salts.— A mixture of Pb2N0 3 , Bi3N0 3 , 
Co2N0 3 , KN0 3 may be dissolved in water and the metals sought 
in the above order (viz. Pb, Bi, Co, K). In testing for acids the 
student will remember that if Pb was found among the metals, 
H 2 S0 4 and HC1 must have been absent, as either would have pre- 
cipitated the lead. If the student forgets this and adds BaCl 2 to 
the solution, it will form a precipitate of PbCl 2 , which he might 
mistake for BaS0 4 , and hence incorrectly suppose H 2 S0 4 to be 
present. 

Mixtures of various other soluble salts should now be given 
out, such as FeS0 4 , NaCl, CuS0 4 , and NH 4 C1; gradually increasing 
tt^e number of metals and acids to be sought. 

8. Analysis of Lime-stone. — Dissolve any piece of marble or 
lime-stone in HC1. It will not be necessary to test for groups I. 
and II.; a small portion of the solution is tested with K 4 FeCy 6 for 
iron. The alumina generally present is precipitated, along with 
the iron, by NH 4 OH, after adding NH 4 C1, and is filtered out as 
rapidly as possible. In a small portion of the filtrate tests are 
made for Ba and Sr, which are of course absent, so that all the Ca 
may be precipitated by oxalate of ammonia. In the filtrate Mg 
will be found on adding Na 2 HP0 4 . The principal acid present 
is COo, as indicated by the effervescence with HC1 when first 
dissolved. If a residue remained insoluble in HC1, it is probably 
Si0 2 , or some silicate, and must be fluxed with Na 2 C0 3 and K 2 C0 3 . 



302 



QUALITATIVE ANALYSIS. 



TABLE I.— SCHEME FOR 



Add HC1 to Solution. 



PREC. 










PLLTRATE 










Ag Pb Hg 
Boil in H 2 

.Qs\7 "PvPP 






Add H 2 S. 






PRECIPITATE. 


1 A ~ -0-„ 






Hg Pb Bi Cd Cu As Sb Sn An Pt. 


Pb 


NH 4 OH 






Digest with yellow (NH 4 ) 2 S. 


3 


&>/. Prec. 




Residue. Solution. 


Ag 


Hg 




Hg Pb Bi Cd Cu 


As Sb Sn An Pt 


w 




p 




Boil in HN0 3 . 


In H apparatus with Zn & H 2 SO * 


b 




i?65. 




Sol. 


Gas. Residue, 


O 


F 


& 










1 

o 


H 




Hg. 




Pb Bi Cd Cn 


AsSb 


Sn Au Pt 


p 




g 




With H 2 S0 4 . 


Pass into 

AgN0 3 


Boil in HC1. 


1 


1 




CO* 
O 


Pra?. 


Sol. 


Sol. Res. 


Sol. Res. 
















e+ 




CD 


Pb 


Bi Cd Cn 


As 


Sb 


Sn 


AnPt 






5' 

p 


£ 


]STH 4 OH. 




and 
Ag 


►3 

CD 


HC1 and 






p 
g 


E. 


Prec. Sol. 




, 


CD 


SW. 




CD 




CD 
CD 






Bi 


Cd Cn 










ag. 






KCy and 


►d 


f 


An 


Pt 








| 


H 2 S 
Prec. Sol. 


P 

CD 


H 

Q 




w 






^ 




CD 




CO 




O 










c+ 










!° 










8) 






Cd. 


Cn 








H 




e+ 














hd 


& 




1 






Hi 


W 






S 


9 » 








O 


3 

O 






CD 


^ ! 




Ul 






3 


CO 












p 








+ 












Q 
































CD 














O 














«1 
















fed 














CD 


















p 













QUALITATIVE ANALYSIS. 



303 



COMPLETE ANALYSIS. 



FILTRATE. 



Add H 2 S. 

FILTRATE. 



Add NH 4 OH and (NHJ 2 S. 
Free. 



Filtrate. 





Co m Ee Cr Mn Al Zn 


Add (NH,) 2 C0 3 . 


' 






Dilute HC1. 




iYw. 


Filtrate. 


Res. 












Ba Sr Ca 
Dissolve in 






Ee Cr Mn Al Zn 






Co Ni. 








Boil in NaOH. 


Acetic Acid ; 


Mg K Xa 




H3 






2 Parts. 


2 Parts. 




8- 


Free. 


<SW. 


/. II. 


/. Z7. 




3 


Ee Cr Mil 


Al 


Zn 




£ 












Euse with KN0 3 


o 




Add 


Ca 


Mg 






O 


and Na 2 C0 3 . Dis- 
solve in H 2 0. 


0Q 


K 2 Cr0 4 
Free. Sol. 


go 


H 
t-H 


1 




_ 


Res. Sol. 


s 


4 




p 


o 


m 4 




4 








o* 




trt- 


s 


Ba 


Sr 


B 


+ 


3 " 




o 












Ee 


Cr 


Mn 


F 

M 


? 


■4 

© 


Pj 


CD 
4 


p 


2 s 




CD 
P 
P 


b 

CD 
QD 


o 

© 


© 
o 


g 

p 




o 

3 


Pi 

Q 

P 


3 




$ p 




p 

CD 

to 

CD 




o 


O 


pi 

p 




4 

© 


O 


o 

PI 


p 
3 






3 
H 


o 

p 
■ + 


© 
P 1 


p* 

pi 




c+-* 
P 


4 
E 

cr 


+ 


CD 


CD t± 
<rt- p 

' B 

CD 




to 


o 






* W 




© 


© 


H 










i> 


3 




o 
M 






o 
o 


O 










O 
k! 

© 
o 

3 




1 






S' 

CO 


o 

1 

c+ 

CD 


Test for NH t in 
the original so- 






Q 
<<! 
QQ 




? 






o 

1 


lution, by heat- 
i n g with 






o 










2 




NaOH, NH 3 is 












given 


off. 





QUESTIONS FOR CLASS USE. 



I. — INTRODUCTION. 

Page 1, 2. — Define chemistry. What is the distinction between 
physical and chemical phenomena? Illustrate. Can matter be 
destroyed? What becomes of it when it disappears? What 
properties do gases possess which prove them to be matter ? What 
is an element ? How many are known ? Is it probable that all 
the elements have been discovered ? What is a compound ? Are 
compounds like their elements? Illustrate. Define chemical 
affinity. Illustrate. How does it act? 

3, 4.— What is the action of heat? Of light? Of electricity? 
Of solution? Illustrate. State the laws of definite and multiple 
proportions. What is the constitution of bodies? What is a 
molecule? An atom? How do atoms differ? What is atomic 
weight? Molecular weight? Yalence? 

5-7. — What notation is used in chemistry? Illustrate. What 
is the formula of a substance? Illustrate. How are reactions 
represented? Illustrate. How are elements named? Com- 
pounds? How are elements classified? What is the distinction 
between Inorganic and Organic Chemistry? 

II. — INORGANIC CHEMISTRY. 
l.-THE NON-METALS. 

11. Oxygen. — Give the symbol and atomic weight of oxygen. 
What is the meaning ? Where is found ? How may it be pre- 
pared ? 

12. — How is prepared from potassium chlorate and manga- 
nese dioxide? G-ive the reaction. What becomes of the potas- 
sium chloride which is formed? 

13-16. — What is the use of the black oxide of manganese? 
Name the properties of 0. What is oxidation? An oxide? 



QUESTIONS FOR CLASS USE. 305 

Show that is a supporter of combustion. What compounds 
are formed in these illustrations? Describe the action of the 
in the air. Describe the action of on fuel. On impure water. 
On writing-ink. On red-hot iron. On damp knives and forks. 
By what means is the carried through the system? 

17, 18. — What work does perform in the body? Why is 
the blood in the arteries red and in the veins blue? What 
chemical processes are included by the chemist under the term 
oxidation? Does fire differ essentially from decay? Is heat 
always produced by oxidation? Illustrate. What is the igniting 
point? How are fires extinguished? What causes spontaneous 
combustion ? 

19, 20. — What is the chemical process of starvation? Why 
d es unusual exercise cause one to breathe more rapidly? Why 
does running cause panting? Why do we need extra clothing 
when we sleep, even at midday, in the summer ? How do hiber- 
nating animals illustrate this ? How does a cold-blooded animal 
differ from a warm-blooded one ? How does give us strength ? 
What is potential energy? Kinetic energy? 

21, 22. — Show how is constantly burning the body. Is 
there any part of the body that is permanent? Illustrate the 
rapidity of this change. Show the truth of the paradox — " VTe 
live only as we die." Why do we need food and sleep? Show 
how acts as a scavenger in nature. In what sense is the 
sweeper of the body ? Is this a useful provision ? How much 
does each adult need per day? Total amount used daily? 

23, 24. — What would be the result if the air were pure ? 
What objects would escape combustion? What is ozone? Where 
is it noticed ? Preparation ? Test ? Properties ? Is it a valuable 
constituent of the air? How does the ozone molecule differ 
from that of ? 

25, 26. — What are the laws for the effects of change of tem- 
perature and pressure on gases? How can the weight of any 
volume of gas be calculated ? How can the weight of a gas 
produced by a given weight of re-agents be found? 

27, 28. Nitrogen. — Symbol and atomic weight? Why so 
called? Sources? Occurrence? Preparation? Properties? Why 
does a person drown in water ? Would a person die in pure N ? 
What is the peculiarity of the nitrogen compounds? 



306 QUESTIONS FOR CLASS USE. 

29, 30. — What causes flesh to decompose so much more 
easily than wood? Does the N we take in at each breath do 
us any direct good or harm? Where do we get N to make our 
flesh? Describe the action of N and in our stoves. Where 
do plants obtain N ? State the main distinction between and 
N. What is the office of the N in the air? Show that the pro- 
portion of and N in the atmosphere gives us the golden 
mean. 

31, 32. — Formula ana molecular weight of nitric acid? Ex- 
plain its occasional presence in the atmosphere. Preparation? 
Properties? What color does it give to wood? Uses? Illus- 
trate its oxidizing action. What is aqua regia? Describe the 
process of etching. The action of HN0 3 on Sn. What are the 
red fumes which pass off? 

33, 34. — Formula and molecular weight of nitrous oxide? 
The common name? Preparation? Reaction? Properties? 
What is the effect of nitrous oxide on the human system? 
State its use in surgical operations. Formula and molecular 
weight of nitric oxide? Its preparation? Why is the gas in 
the flask colored ? What compound is formed with ? Prop- 
erties of NO? What are the fumes which it forms in the air? 

35-37. — Formula and molecular weight of ammonia? Why 
so called? Its old name? What is aqua ammonia? Whence 
obtained ? Give the reaction. Properties ? How liquefied ? De- 
fine the nascent state. 

38, 39. Hydrogen. — Symbol and atomic weight? Meaning 
of the name? Occurrence? Preparation? Reaction? What 
compound is formed? Properties? Is H a metal? Ans. — In 
all reactions it plays the part of a metal, and, like most of the 
metals, is electro-positive. Its levity? Will it destroy life? 
Effect on the voice ? Use in filling balloons ? 

40-44. — What is the product of the combustion of H ? What 
becomes of it ? Will the gases H and O combine, if mixed ? De- 
scribe the hydrogen gun. Cause of the report? What is the 
action of platinum sponge on a jet of H ? Describe Dobereiner's 
lamp. Explain the heat produced by burning H. 

How are hydrogen tones produced? Explain. 

45-47. Water.— Formula and molecular weight of water? 
How may its composition be proved? What is the freezing 



QUESTIONS FOR CLASS USE. 307 

and the boiling point of water? What injury may a small 
quantity of H 2 do, if thrown on a fire? Explain. Can H 2 0, 
then, be burned? Illustrate the abundance of H 2 in the 
animal world. Vegetable world. Mineral world. Why will 
blue vitriol lose its color if heated ? What is ' ' burnt alum " ? 
Water of crystallization? 

48-52. — Show the adaptation of H 2 as a solvent. W^hat 
water is the purest? Why does rain-water taste so insipid? 
Is river-water a healthy drink? What is hard water? Soft 
water? Why does the hardness of water vary in different 
places? Is hard water healthful? How may we detect organic 
matter in H 2 0? What minerals are most common in water? 
What is the "fur" in a tea-kettle? Why does soap curdle in 
hard water? How could Salt Lake be freshened? What is the 
use of the air in H 2 0? How do fish breathe? Does the air 
in water differ from ordinary air? How? Why is boiled 
water so insipid ? Give some of the paradoxes of water. Name 
the various uses of water. ("Physics," p. 201.) 

53-55. Carbon. — Symbol and atomic weight? Illustrate the 
abundance of C. Is it more characteristic of the vegetable than 
of the mineral kingdom? What are its forms? Proof of these 
allotropic states ? What is an allotropic condition ? What is the 
diamond? Properties? Has it ever been made artificially? 
What is a carat? How is the diamond ground? Describe the 
three modes of cutting. What gives the diamond its value? 
Common name for graphite? Origin? Uses of graphite? 

56, 57. — Describe the process of making a lead-pencil. What 
is a black-lead crucible? What is British Luster? Lamp-black? 
Uses? Fitness for printing? What can you say about ancient 
MSS. ? What is soot? What causes the burning of chimneys? 
Does this occur oftener when wood than when coal is used as a 
fuel? How is charcoal made? What is coke? Uses? G-as- 
carbon ? 

58,62. — Bone-black? Uses? How is sugar refined ? Describe 
the formation of coal. Difference between bituminous and 
anthracite coal? Why is coal found in layers, with slate, etc., 
between ? What proof have we that coal is of vegetable origin ? 
Describe the formation of peat. Uses? What is muck? Use? 
Name some of the diverse properties and uses of C. 



308 QUESTIONS FOR CLASS USE. 

63. Carbon Dioxide. — Formula and molecular weight? 
Occurrence? How is it constantly formed? Preparation? Re- 
action ? 

64,65. — Test? What causes the pellicle on lime-water ? What 
does this show? Prove that we exhale C0 2 . Give the proper- 
ties of C0 3 . Prove that C0 2 is heavier than air. A non-sup- 
porter of combustion. That it contains C. 

66, 67. — What test should be employed before descending 
into a deep well or an old cellar ? How can you remove the f ou] 
air? Tell about the Grotto del Cane. Is C0 2 directly poisonous? 
What is choke-damp? Fire-damp? Which is more dreaded? 

68, 69, — Has C0 2 been used in extinguishing fires? Tell 
about the absorption of C0 2 by H 2 0, What is soda-water? 
How is C0 2 liquefied? Why does the liquid solidify when ex- 
posed to the air? What principle in natural philosophy does 
this illustrate? How low a degree of cold has been produced in 
this manner? Describe the need of ventilation. How is the air 
expired from our lungs made useful ? Is a single opening 
sufficient to ventilate a room? What practical application do 
you make of this subject? 

70, 71. — Formula and molecular weight of carbon monoxide? 
Properties? Where is it often formed? Explain. Practical im- 
portance of this fact ? What causes the unpleasant odor of coal- 
gas? Formula and molecular weight of light carburetted 
hydrogen? Properties? How is it formed? 

72, 73. — Name places where it is found in great quantities. 
Formula and molecular weight of heavy carburetted hydrogen? 
Properties ? How made ? What gases mainly compose coal-gas ? 
Which is the most valuable ? Describe the manufacture. Is the 
odor an advantage? Is coal-gas explosive? Why is the jet flat? 
When we turn the gas very low, or the supply is insufficient, 
why is the flame blue? 

74, 75. — What is water-gas? Formula and molecular weight 
of cyanogen? Meaning of the name? Preparation? What are 
its compounds called? What is the yellow prussiate of potash? 
The red? Ans. — The ferricyanide, K 3 FeCy 6 . Properties of Cy? 
What is a compound radical? Formula of hydrocyanic acid? 
Common name? Where found? Antidote? What are the ful- 
minates? How are gun-caps made? 






QUESTIONS FOR CLASS USE. 309 

76, 77. Combustion.— Define. What is a combustible ? A sup- 
porter of combustion? (The difference between these two is 
nicely shown in the experiment with H on p. 40.) A burnt body? 
Ans. — A body which has combined with 0. — Example: a stone, 
water. Upon what does the amount of heat produced by com- 
bustion depend ? The intensity ? Why do we need a draught to 
a stove? Does combustion, in its chemical sense, commence 
before the fuel catches fire? Why do we use ''kindlings" in 
starting a fire? Why can we light pitch-pine so easily? What 
are hydrocarbons? What are the ordinary products of combus- 
tion? What causes the dripping of stove-pipes? What are the 
ashes? Why does fresh fuel produce a flame? Show how ad- 
mirably C is adapted for a fuel. What would be the effect if 
CO 2 were not a gas? Define flame. Describe the burning of a 
candle. Show that flame is hollow. 

78, 79. — What causes the light? Why is the flame blue at 
the bottom? Products of combustion? Tests? Why does the 
wick turn black ? What causes the coal at the end of the wick ? 
Why does snuffing brighten the light ? Why does a draft of air, or 
a sudden movement of the candle, cause it to smoke? Why is 
the flame of a candle or lamp red, or yellow? Ans. — Because 
the heat is not sufficient to cause the carbon to emit all the rays 
of the spectrum. Use of plaited wicks ? Object of a chimney to 
a lamp ? A flat wick ? Advantage of an Argand lamp ? What is 
the film which gathers on the chimney when the lamp is first 
lighted ? Why does this soon disappear ? Why do tar, spirits of 
turpentine, etc., burn with much smoke? 

80-82. — Why does alcohol give much heat and no smoke? 
Describe Davy's safety-lamp. Illustrate this by a wire gauze 
over the flame of a candle. Describe Bunsen's burner. Why 
does it give great heat, little light, and no smoke? Describe the 
oxy-hydrogen blow-pipe. Why does it give great heat and little 
light? What is the calcium light? 

83. — Describe the mouth blow-pipe. The blow-pipe flame. 
Where is the hottest point in the flame? What is the reducing 
flame? The oxidizing flame? Why does blowing on a candle- 
flame extinguish it? 

85-89. The Atmosphere. — Name the constituents. Propor- 
tion. State the comparison. What is diffusion? What effect 



310 QUESTIONS FOR CLASS USE. 

does this have on the air? Is the air a chemical compound? 
Illustrate. Has each constituent a special use? Name the uses 
of 0. Of CO 2 . Explain the chemical change which takes place 
in the leaf. What is the influence of house-plants upon the 
atmosphere of a room ? What can you say of the exact balance 
kept between the wants of animals and plants? 

90, 91. — What relation exists between animals and plants? 
Which gathers and which spends the solar energy? Which per- 
forms the office of reduction? Which that of oxidation? How 
is the solar energy set free? What is the use of the watery 
vapor in the air? Which of the constituents are permanent? 
Is this a wise provision? What effect does this permanence 
have upon sound? Why ought the vapor to be easily changed 
to the liquid form? 

92. The Halogens. — Name them. Symbols and atomic 
weights? Compare the halogens with each other. What com- 
pounds do they form? Why is chlorine so called? Occurrence? 
Preparation ? Reaction ? 

93-95. — Properties of CI? What action does CI have on phos- 
phorus, arsenic, etc. ? Why does a solution of the gas soon 
become acid? What is its action on organic bodies? Why does 
CI act more readily in the presence of moisture? Its action on 
turpentine? On printers' ink? Describe the chemical change 
in domestic bleaching. The method of bleaching on a large scale. 
What is the advantage of using CI over other disinfectants? 

96, 97. — How may the gas be set free? How are hospitals 
purified ? What mixture would liberate CI in the greatest quan- 
tities? Formula and molecular weight of hydrochloric acid? 
Common name? Preparation? Reaction? Properties? What 
are its compounds termed? Tests? What is aqua regia? 

98-100. — What is an acid? A base? A salt? How are acids 
and salts named? Illustrate. Tell what you can about bro- 
mine. Its uses. 

101, 102. — Why is iodine so called? Its source? Properties? 
Test? What is the peculiarity of fluorine? Occurrence? What 
acid does it form? For what is this acid noted? Describe the 
process of etching with HF. Why is not HF kept in ordinary 
bottles? Is it dangerous to use? 

103. Sulphur. — Symbol and atomic weight ? Sources? What 



QUESTIONS FOR CLASS USE. 311 

is the principle of hair-dyes ? Why do eggs tarnish silver spoons ? 
What is the difference between brimstone and flowers of sul- 
phur? Properties? Solvent? Allotropic forms? Describe the 
changes produced by heating. 

104, 105. — Uses of S? Formula and molecular weight of 
sulphur dioxide? Where is it familiar? What is sulphurous 
acid? What salts does it form? Uses of S0 2 in bleaching? 
Why are new flannels liable to turn yellow when washed? 
Formula and molecular weight of sulphuric anhydride? By 
what other name is it known? Preparation? Properties? Why 
is Nordhausen acid so called? 

106, 107. — Formula and molecular weight of sulphuric acid? 
Common name ? State its importance. What are its compounds 
called? Illustrate the making of- H 2 S0 4 . Describe its manu- 
facture. Reaction ? 

108-110. — Properties? What especial property? Illustrate. 
Its strength ? Color of its stain on cloth ? How removed ? On 
wood? Cause of this action? Test? Formula and molecular 
weight of hydrogen sulphide ? Where is it found ? Preparation ? 
Reaction ? Properties ? Use ? Color of the precipitates ? Test ? 
Formula and molecular weight of carbon sulphide? Prepara- 
tion? Properties? Uses? How does it illustrate the force of 
chemical affinity? 

Ill, 112. Yalence. — What is valence? Illustrate. What 
names distinguish the different valence of atoms? What are 
monobasic, bibasic, tribasic acids? What is a normal salt? An 
acid salt? 

113. Phosphorus. — Symbol and atomic weight? Why so 
called? Occurrence? In what parts of the body, and in what 
forms, is it found? 

114-116. — Preparation? Properties? Caution to be observed? 
Is phosphorus poisonous? What is the product of its com- 
bustion? Describe the amorphous form of phosphorus. What 
is the principal use of phosphorus? Describe the making of 
the lucifer match. The safety match. What compounds are 
formed in the burning of a match? What is phosphorescence? 
Its cause? 

117. — Formula and molecular weight of hydrogen phosphide? 
Preparation ? Properties ? 



312 QUESTIONS FOE CLASS USE. 

117-120. Arsenic — Symbol and atomic weight? Common 
name? Test? What is commonly sold as arsenic or ratsbane? 
Preparation of arsenic trioxide ? Properties ? What can you tell 
of its antiseptic property? Antidotes? Describe Marsh's test. 
How can the As be distinguished from Sb? What is said of 
arsenic eating? 

120-122. Boron. — Symbol and atomic weight? Source? 
Describe the scene in Tuscany where it is found. Process of 
obtaining boric acid? Formula and molecular weight of borax? 
Uses? 

123-126. Silicon.— Symbol and atomic weight? Occurrence? 
Common names of Si0 2 ? What gems does it form? What 
is sand? Properties? Why is it called an anhydride? Is silica 
soluble in H 2 0? How does it get into plants? In what plants 
is it found? Explain the process of petrifaction. What is said 
of the antiquity of glass? Pliny's story of its origin? What is 
said of its value in the twelfth century? Name the four va- 
rieties of glass and the composition of each. What are the 
essential ingredients of glass? How is glass colored? Name 
the oxides used. Why is flint-glass so called? How is glass 
annealed? Describe the Prince Rupert's drop. How are Vene- 
tian balls made? Tubes? Beads? 

2 .— T HE M ETA LS. 

127. Potassium. — Symbol and atomic weight? History of 
its discovery? Source? 

128, 129. — How do we get our supply? Preparation? Prop- 
erties? How must it be kept? Reaction when thrown on H 2 0? 
Formula and molecular weight of caustic potash? Properties? 
Its feel? Its affinity for H 2 0? Uses? Formula and molecular 
weight of potassium carbonate? Common name£ Preparation? 
What part of the tree furnishes the most potash? What is the 
derivation of the word? Formula and molecular weight of 
acid potassium carbonate? Common names? Preparation? 
Formula and molecular weight of potassium nitrate? Com- 
mon names? Where is it found? 

130, 131. — How is it prepared artificially ? How much water 
would be required to dissolve a pound of this salt? Properties? 






QUESTIONS FOR CLASS USE. 313 

Uses ? What is the composition of gunpowder ? Cause of its 
explosive force ? Uses of potassium chlorate ? Potassium bi- 
chromate ? Composition of fire-works ? 

Sodium. — Symbol and atomic weight ? Source ? What pro- 
portion does it form of common salt ? 

132, 133. — What element does it resemble? Reaction when 
thrown on water ? What compound is formed ? Test ? Formula 
and molecular weight of common salt? What use does it sub- 
serve in the body? Is salt abundant? Describe the manu- 
facture. What is solar salt? Describe the "hopper-shape" 
crystal. Is it best to heat the water for dissolving salt? What 
is a saturated solution? 

134, 135. — Formula and molecular weight of sodium hydrox- 
ide ? Common name ? Uses ? Formula and molecular weight of 
sodium sulphate ? Common name ? Preparation ? Reaction ? 
What curious property has this salt? Why will the dropping 
in of a crystal cause solidification? Formula and molecular 
weight of sodium carbonate? Common names? Why called 
carbonate of soda ? Describe its manufacture. Why will Na 2 C0 3 
soften hard water? Formula and molecular weight of acid 
sodium carbonate? Common name? Why called bicarbonate 
of soda? Preparation? Use? 

136, 137. — Give the theory of ammonium. How is the for- 
mula NH 4 OH obtained? What is a compound radical? Formula 
and molecular weight of ammonium chloride? Preparation? 
Uses ? Formula and molecular weight of ammonium carbonate ? 
Common names? Uses? Formula and molecular weight of 
ammonium nitrate? Preparation? Uses? 

138,139. Calcium. — Symbol and atomic weight ? Source? In 
what part of the body is it found? In what form do we com- 
monly see it? Formula and molecular weight of lime? Prepa- 
ration? Describe a lime-kiln. Properties of CaO ? Test? What 
is the difference between "water-slaked" and "air-slaked" lime? 
Uses? What is whitewash? Concrete? Hard-finish? Calcimin- 
ing? Theory of the hardening of mortar? Why are newly-plas- 
tered walls so damp? Will mortar harden if protected from the air? 

140. 141. — Action of lime on the soil? Will it not lose its 
beneficial effect after a time ? Should it be applied to a compost 
heap? How can this waste be avoided? How would you test 



314 QUESTIONS FOR CLASS USE. 

for the escaping N H 8 ? Action of lime on copperas ? How does 
the copperas get in the soil? Uses of lime? Formula and 
molecular weight of carbonate of lime? Occurrence? How are 
stalactites and stalagmites formed? What is petrified moss? 
Whiting? Marble? Chalk? Marl? Formula and molecular 
weight of calcium sulphate? Common names? What is plaster 
of Paris? Why does plaster of Paris harden, if moistened? 
Arts. — Because it absorbs water again. 

142, 143. — Uses? What is plaster? How prepared for use as 
a fertilizer? Ans. — It is ground into a fine powder. Tell the 
story of Franklin. What is the difference between sulphate 
and sulphite of lime? Formula and molecular weight of phos- 
phate of lime? What is the superphosphate? Use? Uses of 
the salts of barium and strontium? What is heavy spar? 
Barytes ? 

144. Magnesium. — Symbol and atomic weight? Occurrence? 
How can you tell if a stone contains Mg? Ans. — It generally 
has a soapy feel. Properties? For what is it noted? Product 
of its combustion? Formula and molecular weight of magne- 
sium sulphate? Common name? What is magnesia alba? 

145. Aluminium. — Symbol and atomic weight? Occurrence? 
Properties ? Solvents ? What can you say of its abundance and 
probable usefulness? What is alumina? What crystals and 
gems does it form? 

146. 147. — What is emery? What is common clay? Use in 
the soil ? In the arts ? What is ochre ? Fuller's earth ? Explain 
the process of glazing pottery ware. What is the salt glaze? 
The litharge glaze? What objection to the latter? What gives 
color to brick ? What is the peculiarity of white brick ? How is 
alum made ? Name different kinds of alum. Which kind is the 
common commercial alum? Use of alum in dyeing? How are 
alum crystals made? Ans. — They are obtained by suspending 
threads in a saturated solution of this salt. In this manner 
alum baskets, bouquets, etc., are formed of any desired color. 

148. — What is spectrum analysis? Is it a reliable test? Illus- 
trate its delicacy. What is the spectroscope? 

150. Iron. — Symbol and atomic weight? Tell what you can 
of its value to the world. How is its use a symbol of a nation's 
progress ? 



QUESTIONS FOR CLASS USE. 315 

151, 152. — State how its value is enhanced by labor. Name 
the sources of iron. Common ores. Describe the process of 
smelting iron ore. Why is hot air used for the blast ? Reaction 
of the lime? What becomes of the in the ore? 

153. — Origin of the term "pig-iron"? Name the varieties of 
iron. Difference between them. What is cast-iron? Its proper- 
ties ? Uses ? How is iron adapted for castings ? What is chilled 
iron? Wrought iron? 

154. — Preparation? Effect of jarring? Illustrate its mallea- 
bility. What is steel? Preparation? In making steel tools, 
how does the workman judge of the temper? How are cheap 
knives made? 

155. — Describe Bessemer's process. Cause of the changing 
colors often seen in the scum over standing water? 

156, 157. — Name the different oxides of iron. Give the 
formula of each. What peculiar property is possessed by the 
ferric oxide and ferric hydroxide? What is iron carbonate? By 
what name is it known? Cause of the ferruginous deposit 
around chalybeate springs? Formula and molecular weight of 
iron disulphide ? Common names ? What is chameleon mineral ? 

158, 159. — Uses of iron disulphide? Formula and molecular 
weight of ferrous sulphate? Common names? Uses? 

Zinc. — Symbol and atomic weight? Source? Preparation? 
Reaction? Is it malleable? Will it oxidize in the air? Uses? 
What is philosopher's wool? What is galvanized iron? Are 
water-pipes made of this material safe ? Formula and molecular 
weight of zinc oxide? Use? Formula and molecular weight of 
zinc sulphate? Use? 

160. Tin. — Symbol and atomic weight? Where found? 
Properties? What is the "tin cry"? What is common tin- 
ware? Action of HN0 3 on Sn? What can you say of the manu- 
facture of pins? 

161. Copper. — Symbol and atomic weight? Where found? 
Antiquity of the mines? What is malachite? Properties of Cu? 
Color of its vapor? Solvent? Test? What is verdigris? 

162. 163.— Black oxide of copper? What is the danger of 
using a copper kettle? Formula and molecular weight of cop- 
per sulphate? Common name? Uses? 

Lead.— Symbol and atomic weight? Source? Preparation? 



316 QUESTIONS FOR CLASS USE. 

Properties? Its effect on the human system? Action of water 
on lead? Is there more danger with hard, or with soft water? 
What precaution should always be used with lead pipes ? What 
is the test of lead? What is "litharge"? 

164.— Its uses? "Red-lead"? Its uses? What is "white- 
lead"? Describe its manufacture. With what is it adulterated? 
What is "sugar of lead"? Properties? Antidote? Explain the 
formation of the lead-tree. 

165, 166. Gold. — Symbol and atomic weight? Source? 
Preparation? What is an amalgam? Quartation? Properties? 
Solvent? Process of making gold-leaf? 

167-172. Silver. — Symbol and atomic weight? Source? 
Preparation, 1, from the sulphide; 2, horn-silver; 3, lead? 
Describe the process of reduction at the West. What is cupel- 
lation? Properties of silver? Solvent? Test? What is the 
common name of nitrate of silver? What is its action on the 
flesh? How may its stain be removed? Uses? Of what are 
hair-dyes and indelible inks made? Describe the process of 
Daguerreotyping. Photography. 

173. Platinum. — Symbol and atomic weight ? Source? Prep- 
aration? Properties? Uses? How is very fine platinum wire 
made ? 

174-176. Mercury. — Symbol and atomic weight? Common 
name ? Why so called ? Source ? Preparation ? Properties ? 
Uses? Action on the human system? Process of silvering 
mirrors? What is blue-pill? Mercurial ointment? Formula of 
mercuric oxide? Mercurous chloride? Mercuric chloride? 
Mercuric sulphide? Common names? Uses? Properties? 

The Alloys. — What is an alloy? What peculiarity with re- 
gard to the melting point? Of what is type-metal made? 

177. — Pewter? Britannia? Brass? German silver? Solder? 
Fusible metal ? Bronze ? How is gold soldered ? Silver ? Copper ? 

178. — What is the principle? What are the constituents of 
gold coin? Silver coin? What is the meaning of the term 
carat? How are shot manufactured? How are they sorted? 

179-180. — What is or-molu? Aluminium bronze? Compare 
the properties of the metals with regard to, 1, oxidation ; 2, 
density ; 3, melting point ; 4, color ; 5, malleability ; 6, brittle- 
ness ; 7, tenacity ; 8, special properties. 



QUESTIONS FOE CLASS USE. 317 



III. — ORGAN IC CHEMISTRY. 

185-189. Introduction. — What is organic chemistry? What 
was the first organic substance artificially made? Name some 
which have since been made. What are the organized bodies? 
What elements do organic substances contain? Explain the 
great number of organic substances. What is isomerism? Are 
organic molecules often complex? 

189-192. The Paraffines. — What is the general formula of 
this series of hydrocarbons? Name some of the members. 
Why is the series so called? Source of petroleum? How is it 
purified? What are the products of its distillation? Danger of 
kerosene explosions. How can the kerosene be tested? What 
is paraftine? Bitumen? Its properties? Uses? How may the 
paraffines be artificially made? 

193, 194. The Alcohols. — What is an alcohol? Formula of 
methyl alcohol ? Its source ? Its uses ? Ethyl alcohol — formula ? 
Source? Uses? Effects on the human system? 

195-199. Fermentation. — Cause? Does it ever take place 
spontaneously? How does the yeast act? What change takes 
place in the alcoholic fermentation? The acetic? Describe the 
formation of yeast. The making of malt. Yeast cakes. What 
is gluten ? How does it act ? What is diastase ? Describe the 
brewing of beer. Why is lager beer so called? Describe the 
making of wine. What is the difference between a dry, a 
sweet, and an effervescing wine? Cause of the flavor? State 
the proportion of alcohol in common liquors. How is brandy 
made ? Rum ? Whisky ? Grin ? Describe the apparatus used for 
distillation. What is fusel oil? 

200-204. The Aldehydes and Acids. — What is an alde- 
hyde? Formula of ethyl aldehyde? How is it formed? 
Formula of formic acid? Occurrence? From what is it 
made? Formula of acetic acid? What is glacial acetic acid? 
How is vinegar made? What is cider .vinegar? Pyroligne- 
ous acid? Properties of acetic acid? Use? What causes 
the working of preserves? Where is oxalic acid found? Prepa- 
ration? Properties? Antidote? Uses? WTiere is malic acid 
found? Citric? Where is tartaric acid found? Preparation? 



318 QUESTIONS FOR CLASS USE. 

What is cream of tartar? Tartar emetic? Rochelle salt? 
Seidlitz powders? 

204-209. The Ethers and Ethereal Salts.— What is an 
ether? Formula of ordinary ether? Why called "sulphuric" 
ether? Its properties? Uses? What are ethereal salts? Illus- 
trate. What are the principal fats ? Formula of glycerin ? To what 
class of organic substances does it belong? From what source 
and how is it obtained? Properties? What is nitro-glycerin ? 
Dynamite ? How are candles made ? Illustrate the formation of 
soap. What is the reaction? Difference between hard and soft 
soap ? What is the cause of the curdling of soap in hard water ? 
Describe the cleansing action of soap. What is saponification? 

209, 210. The Halogen Derivatives. — Formula of chloro- 
form? How made? Properties? Iodoform? Chloral? 

211-213. Starch. — Formula? Sources? Use in the plant? 
Why stored in that form? Appearance under the microscope? 
Preparation? Properties? What is dextrin? Test of starch? 
Varieties? What is gum? Composition? Mucilage? Is it 
soluble in water? What is pectose? Pectin? 

213-217. Cellulose.— Formula? What is the composition of 
wood? Name the various forms of cellulin. Illustrate the 
wonders of secretion. State the uses of woody fiber. The 
making of paper. Paper-parchment. Linen. Cotton. Gun- 
cotton. Collodion. Its uses. 

217-220. Sugar. — Cane-sugar? How is sugar refined? Dif- 
ference between loaf and granulated sugar? Describe a centrif- 
ugal machine. What is terra alba? Use? Of what are gum- 
drops made? Rock-candy? What is caramel? Use? Formula 
of grape-sugar? Source? Sweetening power? How is sugar 
made from starch? How does the oil of vitriol act? How do 
jellies, preserves, etc., "candy"? Why are dextrose and levu- 
lose so named? Why must matter be organized? What is the 
office of plants? 

221-225. The Aromatic Compounds. — Formula of benzene? 
Its source? Properties? How is nitro-benzene made? Its 
formula? Uses? Formula of aniline? How made? Proper- 
ties? What is carbolic acid? Picric acid? Naphthalene? An- 
thracene? Benzoic acid? Salicylic acid? Benzoic aldehyde? 
Toluene ? 



QUESTIONS FOR CLASS USE. 319 

225-231. The Terpexes and Camphors.— How do the volatile 
oils differ from the fixed oils? Sources of the essential oils? 
Their preparation? Their composition? Formula of oil of tur- 
pentine? Its properties? What is camphene? Burning fluid? 
Camphor? Its preparation? Properties? What are the resins? 
The balsams? Illustrate. What is the source of rosin? Its 
uses? What is lac? Difference between stick-lac, seed-lac, and 
shellac? How is sealing-wax made? Source of gum-benzoin? 
Uses? Amber? Origin? Properties? Uses? India-rubber? 
Source ? Properties ? Uses ? TThat is vulcanized rubber ? Prop- 
erties ? Gutta-percha ? Uses ? 

231-234. The Alkaloids.— Sources? TThat is opium? Prep- 
aration? Uses? Laudanum? Paregoric? Danger of opium- 
eating? TThat is morphine? Use? Quinine? Use? Nicotine? 
Properties? Strychnine? Properties? The chromatic test? 
Xame the active principle of tea and coffee. TThat substances 
are found in tea ? In coffee ? Describe the process of tea-raising. 
Of making black tea. Green tea. 

235-239. Dyes axd Dyeixg. — Source of organic coloring 
principles? TThat is an adjective color? A substantive color? 
A mordant ? The process of dyeing ? Of calico printing ? TThat 
is madder? Its coloring principle? Cochineal? Use? Brazil- 
wood ? Use ? Indigo ? Preparation ? TThite indigo ? Logwood ? 
Litmus ? Leaf-green ? Tannin ? Xame its varieties. TThat are 
nut-galls? Properties of tannin? Describe the process of tan- 
ning. How is leather blackened? How is ink made? Why 
does writing-fluid darken by exposure to the air? TThat is 
gallic acid ? Pyrogallic acid ? Use ? 

239-243. Albumlxous Bodies.* — TThat is their composition? 

* Xotiee here the wise provision of nature. Kitrogen. slow and sluggish 
when uneonibined. is fitted to dilute the air ; while X, restless and uneasy 
when combined, is equally adapted to forni unstable compounds of food, to 
carry force into our bodies and there to quickly set it free. Oxygen, 
when free, is active, eager, and ready to search the nooks and crannies of 
the capillaries ; but when once it combines with a substance, takes it for 
better or for worse, and forms the stablest of compounds. We find nitrogen 
compounds in the animal and vegetable worlds, ready for use where they 
are needed, in our muscles. Oxygen compounds are abundant in the mineral 
world, and stored in the seeds of plants, at hand to give form to the more 
permanent parts of the body. Such profound relations, such nice adapta- 



320 QUESTIONS FOR CLASS USE. 

What is albumin? Source? Properties? Casein? Why does 
milk curdle ? Action of rennet ? Why does cream rise on milk ? 
Describe the souring of milk. Fibrin? Properties? Gluten? 
Legumin ? Putrefaction ? Cause ? Why does salt preserve meat ? 
What is gelatin ? Grlue ? Isinglass ? Size ? 

243-247. Domestic Chemistry. — Describe the chemical 
changes which take place in making bread. What is stale 
bread ? Why is it dry ? How is aerated bread made ? Why is 
bread ever sour ? How are griddle-cakes raised ? Biscuit ? What 
are baking-powders? Action of soda and HC1? Of sal-volatile? 
How is bread changed by toasting? How are potatoes changed 
by cooking? 

tions of our bodies to the world around, give us glimpses of a creative skill 
worthy of our noblest thought and highest admiration. 



INDEX 



This Index includes the Notes as well as the Text. 



PAGE 

Acid, Acetic 201 

" Benzoic 224 

" Boric 120 

" Carbolic 223 

44 Carbonic 63 

" Citric 203 

" Formic 200 

" Fulminic 75 

" G-allic 238 

44 Hydrochloric. 96 
" Hydrocyanic . 75 
44 Hydrofluoric . 102 

44 Lactic 240 

44 Malic 203 

44 Muriatic 96 

44 Nitric 30 

44 Oleic 202 

44 Oxalic 203 

44 Palmitic 202 

44 Picric 224 

44 Prussic 75 

44 Pyrogallic 238 

' 4 Pyroligneous.. 201 

44 Salicylic 224 

44 Stearic 202 

44 Sulphuric 105 

44 Sulphurous.... 104 
44 Sulphydric. . . . 109 

44 Tannic 237 

44 Tartaric 203 

Acids 98, 200 

Air 85 

Albumin 239 

Albuminoids, Veg.. 242 

Alcohol, Amyl 199 

44 Effects of. 194 

Ethyl 194 

Methyl.... 193 

Alcohols, The 193 

Aldehyde, Benzoic. 224 

Ethyl.... 200 

Aldehydes, The 200 



PAGE 

Alizarin 236 

Alkalies 99 

Alkaloids 231 

Alloys 176 

Alum 147 

Alumina 145 

Aluminium 145 

44 Bronze.. 179 

44 Silicate. 146 

Amalgam 174 

Amber 229 

Ammonium 136 

Ammonium Carb. . . 137 

Ammonium Chlor. . 136 

44 Mtrate 137 

Ammonia 35 

Amyl Acetate 206 

44 Valerianate. 206 
Anhydride, Sulph... 105 

Aniline 222 

Animal charcoal.... 58 

Anthracene 224 

Antimony 176 

Aqua ammonia 35 

Aqua f ortis 32 

Aqua regia 32, 97 

Aromatic comp'nds 221 

Arsenic 117 

44 Eating 120 

44 Trioxide.... 118 
Arseniuretted hy- 
drogen 120 

Asphaltum 191 

Asphyxia 66 

Atomic weight 4 

Atoms 4 

Atmosphere 85 

Atmosphere, Per- 
manence of 91 

Balsams 227 

Barium 143 



PAGE 

Barium Chloride. . . 143 

Bases 99 

Beer 197 

Benzene 221 

Benzine 190 

Benzol 221 

Bessemer's process 

for making steel 155 
Binary compounds. 6 

Bismuth 177 

Bitumen 191 

Blast-furnace 152 

Bleaching 95 

Bleaching-powder... 143 

Blow-pipe 83 

Blow-pipe, Oxyhy- 

drogen 81 

Bones 242 

Bone-black 58 

Borax 121 

Boron 120 

Brass 177 

Brazil wood 236 

Bread 243 

Brimstone 103 

Britannia- ware 177 

Bromine 100 

Bronze 177 

Bunsen burner 81 

Burning-fluid 227 

Butter 206 

Cadmium 144 

Caesium 137 

Caffeine 234 

Calcimine 139 

Calcium 138 

44 Carbonate.. 140 
Chloride.... 143 
44 Hydroxide. 139 
44 Hypochlo - 

rite 143 



322 



INDEX. 



PAGE 

Calcium-Light 82 

Oxide 138 

" Phosphate.. 142 
Sulphate.... 141 
Sulphite.... 142 

Calico-printing 235 

Calomel 176 

Camphene 227 

Camphor 227 

Candles 207 

Caoutchouc 229 

Carat 54, 178 

Caramel 219 

Carbon 53 

" Amorphous. 56 

" Dioxide 63 

" Monoxide. . . 70 
" Disulphide.. 110 

Carbonic Acid 63 

Carburetted hydro- 
gen 72, 73 

Carmine 236 

Case-hardening. ... 154 

Casein 240 

Cast-iron 153 

Cells 214 

Cellulin 214 

Celluloid. 217 

Cellulose 213 

Chalk 140 

Charcoal 57 

" Animal — 58 

Cheese 240 

Chemical Affinity. . . 2 
Chem. Harmonica.. 43 

Chemism 2 

Chemistry, Inorg. . . 7 

Org.... 7, 185 

" of candle 77 

" lamp.. 79 

" fire.... 75 

" Domestic 243 

Chilled iron.... 153 

Chlorine 92 

Chloroform 209 

Chlorophyl 237 

Chloral 210 

Choke-damp 67 

Chrome yellow 131 

Chromium 131 

Cinnabar 174 

Cider 201 



PAGE 

Classification 6 

Clay 146 

Coal 58 

" -gas 72 

Cobalt 117 

Cochineal 236 

Coin 178 

Coke 57 

Collodion 217 

Combustion 17, 75 

Compound ethers... 205 

Compounds 2 

Concrete 139 

Confectionery 218 

Constitution of Bod- 
ies 3 

Copper 161 

" Acetate 161 

" Carbonate... 161 

" Oxide 162 

Sulphate .... 162 

Copperas 158 

Coral 140 

Corrosive sublimate 176 

Cotton 217 

Cream 240 

Cream of tartar — 204 

Creosote 193 

Cupellation 168 

Cyanogen 74 

Daguerreotype 171 

Davy's Safety Lamp 80 
Definite proportions 3 

Dextrin 212 

Dextrose. 219 

Diamond 53 

Diastase 196 

Diffusion, Law of.. 86 

Disinfectant 95 

Distillation 198 

Drummond Light. . 82 

Dyeing 235 

Dynamite 207 

Efflorescence 48 

Elements 1 

Table of... 257 

Equations 5 

Essences 225 

Etching 32, 102 

Ether 205 



PAGE 

Ethereal Salts 205 

Ethers, Compound. 205 

Mixed 205 

The 204 

Ethyl Alcohol 194 

" Butyrate 206 

Eats 206 

Fermentation 195 

Eerrous Sulphate... 158 

Eibrin 241 

Eire-damp. 71 

Eire- works 130 

Eish, Breathing of. 50 

Elame 77 

Eluorine 101 

Eormulas, Constitu- 
tional 188 

Eulminates 75 

Eusel oil 199 

Eusible metal 177 

Galena 162 

Galvanized iron 159 

Gas-carbon 57 

Gas, Illuminating.. 72 
" Diffusion of. . . 86 

11 Olefiant 72 

Gases, Weighing and 

measuring 24 

Gelatin 242 

German silver 177 

Glass 124 

Glazing of pottery.. 146 

Glucinum 144 

Gluten 196, 243 

Glue 243 

Glycerin 206 

Gold 165 

Graphite 55 

Gum Arabic 213 

" Benzoin 228 

Gun-cotton 217 

Gunpowder 130 

Gutta-percha 231 

Gypsum 141 

Halogens 92 

Hartshorn 35 

Heat 3,17 

Hematite 156 

Hydraulic lime 139 



INDEX. 



323 



PAGE 

Hydrocarbons 189 

Hydrogen 38 

Hydrogen sodium 

carbonate 135 

Hydrogen sulphide. 109 
Hydrogen, Heavy 

carburetted 72 

Hydrogen, Light 

carburetted 71 

Hydrogen phos- 
phide 117 

Igniting-point 17 

India-rubber 229 

Indigo 236 

Ink 238 

" Printers' 239 

Iodine 101 

Iodoform 210 

Iridium 173 

Iron 150 

" Carbonate 157 

" Cast 153 

" Disulphide 157 

" Oxides 156 

" Pure 156 

14 Sulphate 158 

" Wrought 153 

Isomerism 18S 

Kekosene 190 

Lac 228 

Lampblack 56 

Laudanum 232 

Laughing-gas 33 

Lead 162 

11 Acetate 164 

41 Black 55 

44 Carbonate 164 

41 Oxides 163 

44 Bed 164 

44 Sugar of 164 

44 Tree 164 

44 White 164 

Leather 238 

Leblanc's process... 134 

Legumin 242 

Light 3 

Lime 138 

14 Chloride of.... 143 

44 Phosphate of.. 142 



PAGE 

Lime, Slaked 139 

44 Superphos- 
phate of... 142 

Lime-Light 82 

Limestone 140 

Linen 216 

Lithium 137 

Litmus 237 

Litharge 163 

Logwood 237 

Luminous paint 117 

Lunar caustic 170 

Lye 129 

Madder 236 

Magenta 223 

Magnesium 144 

44 Carbon. 145 

Sulph... 145 

Malleable iron 153 

Malt 196 

Manganese 157 

Marble 140 

Marl 140 

Marsh-gas 71, 189 

Marsh's test 119 

Matches 114 

Mauve 222 

Mercuric Oxide 175 

Sulphide.. 176 

Mercury 174 

44 Chlorides . . 176 

Metals 127 

44 Alkalies 127 

Metals, Alkaline 

earths.... 138 

44 Noble 165 

44 Properties 

of 179 

Useful 150 

Methyl Alcohol 193 

Milk 240 

Mirrors 175 

Mixed gases 40 

Molasses 218 

Molecular Weight. . 4 

Molecules 4 

Mordants 235 

Morphine 232 

Mortar 139 

Muck 60 

Multiple proportions 3 



PAGE 

Naphtha 224 

Naphthalene 224 

Nascent state 37 

Nickel 177 

Nicotine 233 

Niter 129 

Nitric oxide 33 

Nitro-Benzene 222 

44 Glycerin 207 

44 Toluene 225 

Nitrous oxide 32 

Nitrogen 27 

Nomenclature 5 

Nordhausen sulph. 

acid 105 

Notation 5 

Oil, Bitter almonds. 224 

44 Pusel 199 

44 Kerosene 190 

44 Linseed 238 

44 Turpentine 226 

44 of vitriol 105 

Oils, Volatile and 

essential 225 

Oleflant gas 72 

Olein 206 

Opium 231 

Organic Chem 7,185 

Organizat'n of mat- 
ter 220 

Organized Bodies. . . 185 

Or-Molu 179 

Osmium 173 

Oxygen 11 

Oxyhydrogen blow- 
pipe 82 

Ozone 23 

Palladium 173 

Palmitin 206 

Paper 215 

Parafiine 191 

Paranlnes, Artiflc'l 
preparation of.. 192 

Paraffines, The 189 

Parchment 216 

Paregoric 232 

Pearlash 128 

Peat 59 

Pectin , 213 

Pencils 56 



324 



INDEX. 



PAGE 

Percussion caps 75 

Permanence of at- 
mosphere 91 

Petrifactions 123 

Petroleum . . 190 

Pewter 177 

Phenol 223 

Phosphorescence.. . . 115 

Phosphorus 113 

Phosplmretted hy- 
drogen 117 

Photography. 171 

Pitch 228 

Plants in the room.. 88 
Plants, Office of.... 90 

Plaster of Paris 141 

Platinum 173 

Plumbago 55 

Potash, Bicarb, of.. 129 
Bitartr'teof 204 

Caustic 128 

Carbon, of. 128 
Nitrate of.. 129 

Potassium 127 

" Acid Carb. 129 
" Bichrom. . 131 
" Carbonate 128 
Chlorate.. 131 
" Nitrate.... 129 

Oxide 128 

Pottery 146 

Prac. Questions.. 26, 37, 
52, 84, 110, 148, 181, 247 

Preserves 202, 220 

Prussic acid 75 

Putrefaction 242 

Putty 239 

Pyroxylin 217 

Quartation 165 

Quartz 122 

Quicksilver 174 

Quinine 232 

Red precipitate 175 

Rennet 240 

Resins 227 

Rhodium 173 

Rochelle salt 204 

Rosaniline 223 

Rosin 228 



PAGE 

Rubidium 137 

Ruthenium 173 

Sal-ammoniac 136 

Saleratus 129 

Sal-soda 134 

Salt, Common 132 

" Epsom 145 

" Glauber's 134 

" Rochelle 204 

Salts 99 

Saltpeter 129 

Sal-volatile 137 

Sand 109 

Secretion 214 

Seidlitz powders 204 

Shellac 228 

Shot 178 

Silicon 122 

Silica 123 

Silicates 124 

Silver 167 

" Chloride 172 

" Nitrate 170 

Smelting 151 

Soap 207 

Soda, Bicarbon'te of 135 
" Carbonate of.. 134 

44 Caustic 134 

Sodium 131 

Amalgam.. 136 

" Carbonate.. 134 

Chloride.... 132 

" Hydroxide. 134 

Nitrate 135 

Sulphate.... 134 

Solar energy 90 

Solder 177 

Solution '. — 3 

Soot 57 

Spectrum analysis.. 147 
Spongy platinum.42, 173 
Spontaneous com- 
bustion 18 

Stalactites 140 

Stalagmites 140 

Starch 211, 219 

Stearin 206 

Steel 154 

Strontium 143 

Strychnine 233 



PAGE 

Sucrose 217 

Sugar, Cane 217 

" Grape 219 

" Milk 240 

44 of lead.. 164, 201 

Sulphites 104 

Sulphur 103 

" Dioxide .... 104 
" Trioxide. . . 105 
Sulphuric Anhydr.. 105 
Sulphuretted hydro- 
gen 109 

Symbols 5 

Tannin 237 

Tanning 237 

Tartar emetic 204 

Theine. 234 

Tea 234 

Tin 160 

Toluene 225 

Turpentine 226 

Type-metal 176 

Tyrian purple 236 

"Valence 4, 111 

Verdigris 161 

Vermilion 176 

Ventilation 69 

Vinegar 201 

Vitriol, Blue 162 

Green 158 

" Oil of 105 

White 159 

Water 45 

Water-gas 74 

Wax, Sealing 228 

White-lead 164 

White-wash 139 

Whiting 141 

Wines 197 

Woody fiber 213 

Yeast 196 

Zinc 158 

" Chloride 159 

11 Oxide 159 

44 Sulphate 159 

44 White 159 



GLOSSARY. 



A 

a9 / e tat^ 

a (pet/i-e 

a-e tin 7 ie 

affinity 

al bu' min 

al bu'mi nous 

al'el&e mist 

al' de hyd^ 

a liz' a rin 

al' ka II 

al lo trdp' i-e 

al loy' 

al u mm'i una 

a mal'gam 

am mo'ni a 

am mo ni' a-e al 

a mdr'phous 

am'yl 

an aes thet' i-e 

an hy'drid^ 

an hy' drous 

an'i lm^ 

an'thra 9en^ 

an'ti mo ny 

a' qua 

ar gen' turn 

ar' se nie 

ar se nl' u ret ted 

ar' ter y 

as phyx' i a 



at'om 
a torn' i-e 
au' glt^ 

B 

ba' ri um 

ba ry' te§ 

ben'zen^ 

ben zo' i-e 

ben'zol 

ber'yl 

bl ba' sie 

bl ear' bo nat^ 

bl' na ry 

bl nox'id^ 

bi tu'men 

bi tu'mi nous 

biv' a lent 

bo' rax 

bo' rie 

bo' ron 

bro'min^ 

bru' 9in^ 

bu'ty rat^ 

bu tyr'i-e 

C 

eae' §i um 
-eaf fe'in^ 
eaf fe o tan'ni-e 
eal ea' re ous 
■eal £ln^d' 



eal' 91 um 
eal'o mel 
eam'phen^ 
eaout'choue 
(kob'chdok) 
eap' il la ry 
ear' bo hy drat^ 
ear fool' ie 
ear bo na'ceous 
ear' bon at^ 
ear box' yl 
ear' bu ret 
ear' fou ret ted 
ear' mln^ 
ea'se in 
eaus'ti-e 
9el'lu lin 
9el'lu loid 
9el'lu los^ 
ehal 9ed'o ny 
-eha lyfo'e at^ 
e^em'i§m 
e)$.em'is try 
e^lo'ral 
e^lo' rm^ 
e^lo'ro form 
elalo'ro phyl 
ei3.r0 mat' i-e 
ei^rys' o pra§^ 
eln' na bar 
91 1' ri-e 



326 



GLOSSAKY. 



•eo'balt 
■edeh' i ne^l 
■eol 16' di on 
■eop' per as 
■ere'o sot^ 
■eu pel' 
€u pel lotion 
ey'a nid^ 
ey an' o gen 
eym' o gene, 

D 

de ox' i diz^ 
dex' trln 
d£x' tro§e, 
di' as tas^ 
di ox' id^ 
di stir phid^ 
doro mite, 
dy' na mlt^ 

E 

£b' on It^ 

e le-e trdl' y sis 

eth'yl 

F 

fer' ri-e 
fi'brin 
fr-eus 
flu' or in®, 
ful'minat^ 
ful min' i-e 
fu' sel 

G 

ga le' na 
gal lo-tan' ni-e 
gas'o lin^ 
ga§ om'e ter 
gel 7 a tin 



glob' ul^ 
glu' ten 
gl^ye'er in 
graph' It^ 

H 

hal' o gen 
ha'loid 
hem' a tlt^ 
horn'blend^ 
hy drau'li-e 
hy dro bro' mic 
hy dro -ear'bon 
hy dro -el^lo'ri-e 
hy dro ey an' i-e 
hy'dro gen 
hy drox'yl 
hy dro z6' a 
hy po el^lor' Ite, 

I 
V o di$^ 
I' o din^ 
I 6d' o form 
I so mer' i-e 
I som'er i§m 
I so mdrph' ous 



jar go nel\e/ 

K 

kelp 

ker' o sen^ 

ki net' i-e 



la-e 

lau'da num 
le gu' mm 



li'-el^en 
lith'arg^ 
lith' i um 
lit' mus 

M 

mag ne'si um 
mar a -e^It^ 
ma' li-e 
man ga ne§©/ 
mauve (mov) 
meer' s^hat^m 
mer -eu' ri-e 
mer' -eu rous 
mer'cu ry 
mir' ban^ 
mo lee' u lar 
mol'e -eul^ 
mon o ba' si-e 
mo nox'id^ 
in or' d ant 
mor' phin^ 
muri at' i-e 

N 
naph'tha 
ni-e' o tine, 
nl' trat^ 
nl' ter 
nl' tri-e 
nl' tro gen 

O 

o'-el^ry 

6-e ta he' dral 

ce nan' thi-e 

6' le fl ant 

o'lein 

o' pi um 



GLOSSARY. 



327 



or mo lu 7 

ox al'i-e 

ox i da 7 tion 

6x 7 y gen 

ox y hy 7 dro gen 

6' zon^ 

P 

pal mit'i-e 
pal'mi tin 
par 7 af flne^ 
pe-e 7 tos^ 
pen tox'id^ 
per man'gan ate^ 
phenol 
phe 7 nyl 
phos' phm^ 
phos'phu ret ted 
pi 7 eri-e 
plat 7 i num 
plum ba 7 go 
po tas 7 si um 
pro'tein 
prus' si at^ 
prus 7 si-e 
py ri 7 te§ 
pyr o gal" li-e 
pyr o llg 7 ne ous 
py rox 7 y lin 



quad rlv 7 a lent 
quer ei tan 7 ni-e 
qui 7 nln^ 
quartz 



res/m 
rfcug' o len^ 
ro§ an' i lin^ 
ros/ in 
ru bid 7 i um 



sal-am mo'ni a-e 

sal e ra. 7 tus 

sal i eyl 7 i-e 

sa pon i fi -ea 7 tion 

sar'do nyx 

sejd 7 litz 

sel 7 e nit^ 

ses qu!-ear 7 bo nat^ 

ses qui ox'id^ 

sheTlae 

sl r lex 

sir i -eat^ 

sir i -eon 

smalt 

so 7 di um 

sor'g^um 

spath 7 ie 

spe-e 7 u lum 

sperm a ee 7 tl 

spor 7 ul^ 

sta la-e'tit^ 

sta lag 7 mit^ 

stan' ni-e 

stannous 

ste ar 7 i-e 

ste 7 a rin 

stom 7 a ta 



stron 7 ti an it& 
stron 7 ti um 
strye V nine, 
su' -eros^ 
sul'phur 
su.1 7 phu ret ted 
sulph y 7 dri-e 

T 

tar tar 7 i-e 
ter 7 pen^s. 
tet 7 a nus 
the'In^ 
the i tan 7 ni-e 
tol 7 u en^ 
to lu 7 1 din^ 
trl ba 7 si-e 
trl o 7 le at^ 
trlpalmi 7 tat^ 
trl ste 7 a rat^ 
triv 7 a lent 
tur' pen tin^ 

U 

u. niv 7 a lent 
u/pas 
u/re a 

V 

val 7 ene^ 
ver 7 di gris 
vlt 7 ri ol 
vul 7 ean It^ 

Z 

zaf'fer 



Burnet's Zoology 

FOR 

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BY 

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